{"content_id":"zzsvd5wsyq","slug":"salsu-battle-612-eulji-mundeok-strategy-and-significance","locale":"en","schema_type":"Article","category":"knowledge_base","category_name":"Knowledge Base","title":"Battle of Salsu 612: Eulji Mundeok's Strategy","summary":"The Battle of Salsu was a 612 battle in which Goguryeo defeated the Sui forces advancing on Pyongyang. It centered on Eulji Mundeok's reconnaissance and lure tactics and an attack during a river crossing as the enemy retreated. Troop figures and the flood theory must be read with attention to the scope of each historical record.","sponsorship_disclosure":null,"affiliate_disclosure":null,"commerce_disclosure":null,"author":{"name":"Injoys Editorial Team","url":"https://injoys.com/ko/about"},"key_points":["The Battle of Salsu was a battle in the seventh lunar month of 612 in which Goguryeo decisively defeated the Sui forces at the Salsu River.","Eulji Mundeok inspected the enemy camp under the guise of surrender, then lured the Sui forces onward.","Goguryeo attacked the Sui rear guard when the retreating forces were halfway across the Salsu River.","The figures of 305,000 and 2,700 in the Samguk Sagi refer respectively to the initial strength of the nine armies and the number who returned to Liaodong Fortress.","The Battle of Salsu thwarted the 612 campaign, but it did not end the Sui dynasty's later invasions."],"content_markdown":"The Battle of Salsu was a battle in 612 in which Goguryeo repelled an invasion by the Sui dynasty. Eulji Mundeok lured the enemy deep into Goguryeo territory, then attacked as it crossed the Salsu River during its retreat. It is remembered as a victory that thwarted a large expeditionary force's assault on Pyongyang.\n\nThis article follows the *Samguk Sagi* in the Korean History Database and was checked in September 2026.\n\n## When and where did the Battle of Salsu take place?\n\nThe Battle of Salsu took place in the seventh lunar month of 612, the 23rd year of King Yeongyang's reign. The Salsu River is generally identified as today's Chongchon River. The Goguryeo commander was Eulji Mundeok. His opponents were the Sui forces advancing toward Pyongyang under Yu Zhongwen, Yuwen Shu, and others.\n\nThis battle was one part of the war between Goguryeo and Sui. The entire Sui army did not gather and fight at a single location on the Salsu River. The troops attacking Liaodong Fortress must be distinguished from those heading toward Pyongyang. Basic information about the battle is available in the [Encyclopedia of Korean Culture entry on the Battle of Salsu](https://encykorea.aks.ac.kr/Article/E0026415).\n\n## Background to the Sui invasion\n\nThe war arose from a conflict between the two states over the East Asian order. Sui unified China in 589. It then sought to expand its influence over neighboring states. Goguryeo sought to preserve its existing independent sphere of influence.\n\nIn 598, Goguryeo attacked Liaoxi first. Emperor Wen of Sui responded by sending an army, but the campaign failed. His successor, Emperor Yang of Sui, personally launched a campaign against Goguryeo in 612. This sequence is outlined in [Our History Net's explanation of the Goguryeo-Sui War](https://contents.history.go.kr/front/kc/printViewPopup.do?levelId=kc_i100400).\n\nGoguryeo faced multiple attacks that extended as far as its capital. The main Sui forces put pressure on the fortresses of Liaodong. Nine armies under Yu Zhongwen, Yuwen Shu, and others advanced toward Pyongyang. The Sui navy commanded by Lai Hu'er also approached by sea.\n\n## Timeline from the invasion to the retreat\n\nThe Battle of Salsu progressed from reconnaissance of the enemy camp to luring the enemy in and attacking it during its retreat. The months below follow the lunar calendar used in the historical sources. They have not been converted to Gregorian dates.\n\n| Period | Event | Source |\n| --- | --- | --- |\n| 589 | Sui unifies China | Our History Net, “Goguryeo-Sui War” |\n| 598 | Goguryeo attacks Liaoxi and Emperor Wen of Sui's campaign fails | Our History Net, “Goguryeo-Sui War” |\n| 612 | Emperor Yang of Sui launches a large-scale invasion of Goguryeo | Our History Net, “Battle of Salsu” |\n| Sixth lunar month of 612 | Eulji Mundeok conducts reconnaissance of the Sui camp | *Samguk Sagi*, “Biography of Eulji Mundeok” |\n| Seventh lunar month of 612 | Goguryeo attacks the retreating Sui forces at the Salsu River | *Samguk Sagi*, “Biography of Eulji Mundeok” |\n| 613 | Sui invades again but withdraws after Yang Xuangan's rebellion | Our History Net, “Goguryeo-Sui War” |\n| 614 | After another Sui invasion, the war ends with Goguryeo's request for peace | Our History Net, “Goguryeo-Sui War” |\n\n## Eulji Mundeok's reconnaissance and luring strategy\n\n### What did he learn through a false surrender?\n\nThe *Samguk Sagi* explains that Eulji Mundeok visited the enemy camp to conduct reconnaissance. Under royal orders, he entered the Sui camp under the pretense of surrendering. His actual purpose was to examine the opposing army's strengths and weaknesses. This is stated in the [reconnaissance account in the “Biography of Eulji Mundeok”](https://db.history.go.kr/common/compareViewer.do?levelId=sg_044r_0020_0040\u0026type=ancient).\n\nThe Sui commanders tried to capture Eulji Mundeok. However, Liu Shilong opposed this, and they let him return. Eulji Mundeok did not respond when they asked him to come back. The record states that he then crossed the Yalu River and returned.\n\n### Why did they starve despite receiving so many provisions?\n\nThe supply problem arose from the gap between the amount of food issued and the troops' actual ability to carry it. The nine armies reportedly received 100 days' worth of food when they departed. The soldiers also had to carry weapons and other military supplies. There are records of soldiers burying food because they could not bear the heavy loads.\n\nThe mere fact that food was issued therefore does not mean the supply effort succeeded. Enough food had to remain for the advance to Pyongyang. As the campaign continued, this condition broke down. The Encyclopedia of Korean Culture describes this as an operational constraint on the nine armies.\n\n### Why did they pretend to lose and retreat?\n\nEulji Mundeok's retreat was a luring operation intended to draw the enemy deeper into Goguryeo territory. Our History Net describes the seven battles fought in one day as deliberate defeats. The Sui forces exhausted themselves even as they won the battles. The troops that eventually advanced to the vicinity of Pyongyang faced supply shortages and fatigue.\n\nEulji Mundeok sent Yu Zhongwen a poem calling for an end to the war. However, the poem alone cannot be seen as the reason for the decision to retreat. The shortage of provisions and the difficulty of taking Pyongyang Fortress must also be considered. A related explanation appears in [Our History Net's account of the Battle of Salsu](https://contents.history.go.kr/mobile/kc/view.do?code=kc_age_10\u0026levelId=kc_i101200).\n\n## The turning point was the retreat and river-crossing attack\n\nThe decisive turning point came when the Goguryeo forces continued to pressure the retreating enemy. Eulji Mundeok sent an envoy to propose surrender once again. He offered to arrange an audience between the Goguryeo king and the emperor if the Sui forces withdrew. The exhausted Sui commanders used this as a justification to retreat.\n\nThe *Samguk Sagi*'s “Biography of Eulji Mundeok” describes the ensuing attack as follows.\n\n\u003e Eulji Mundeok sent out his troops, surrounded the enemy on all sides, and attacked.\n\nThe Sui forces moved while fighting in a square formation. A square formation was designed to defend against attacks from multiple directions. When about half of the troops had crossed the Salsu River, the Goguryeo forces attacked the rear guard. The record states that the collapse of the rear units spread to other units.\n\nFrom a tactical perspective, units can easily become divided while crossing a river. This interpretation explains their vulnerability during the crossing. The historical source directly identifies the rear guard as the target of the attack. The evidence comes from the [account of the Battle of Salsu in the “Biography of Eulji Mundeok”](https://db.history.go.kr/common/compareViewer.do?levelId=sg_044r_0020_0110\u0026type=ancient).\n\n## Troop figures and the outcome of the battle\n\nThe figures in the *Samguk Sagi* show the major defeat suffered by the nine armies that advanced toward Pyongyang. However, the difference between the number of departing troops and returning troops is not necessarily the number killed. The locations and counting scopes represented by the two figures must be distinguished.\n\n| Recorded figure | Period and scope | Points to note when interpreting |\n| --- | --- | --- |\n| 1 million | Figure reported as the number mobilized for the Sui campaign in 612 | Not the number of troops gathered at the Salsu battlefield |\n| 305,000 | Strength of the nine armies when they first crossed the Liao River in 612 | Starting size of the force advancing toward Pyongyang |\n| 2,700 | Number who returned to Liaodong Fortress after the defeat in 612 | Cannot be treated as the total number of survivors from the entire expeditionary force |\n\nThe first figure is given in Our History Net's account of the Battle of Salsu. (verified figure: 1,133,800 soldiers and twice that number of provisions carriers · source: contents.history.go.kr · checked 2026-09-23) The latter two figures come from the *Samguk Sagi*'s “Biography of Eulji Mundeok.” (verified figures: 305,000 troops in the nine armies that first crossed the Liao River, 2,700 who returned to Liaodong Fortress · source: db.history.go.kr · checked 2026-09-23) These records do not reveal the exact strength or losses of the Goguryeo forces.\n\nThe Battle of Salsu sealed the failure of Sui's 612 campaign. Emperor Yang of Sui ultimately withdrew his army. However, Sui attacked Goguryeo again in 613 and 614. This victory therefore cannot be regarded as the immediate end of the entire war between the two states.\n\nSui's fall is also difficult to explain through a single battle. Repeated campaigns increased the burden on the state. Large-scale civil engineering projects and internal rebellions also played a role. This background is described in Our History Net's explanation of the Goguryeo-Sui War.\n\n## Records and interpretations\n\n### What the historical source directly states\n\nThe *Samguk Sagi* recounts the reconnaissance, luring operation, and attack during the retreat. However, it is not a report written at the scene in 612. It is a historical work compiled in Goryeo by Kim Busik and others in 1145. Its date of compilation is given in [Our History Net's explanation of the *Samguk Sagi*](https://contents.history.go.kr/mobile/kc/view.do?levelId=kc_r200340).\n\n### The commonly accepted explanation\n\nPublic history resources identify the luring operation and supply difficulties as key factors in the outcome. This explanation is shared by Our History Net and the Encyclopedia of Korean Culture. The ability of Liaodong's fortresses to hold out must also be considered. Eulji Mundeok's strategy can be understood within the broader conditions of the war.\n\n### Is the flood attack theory a confirmed fact?\n\nThe claim that Goguryeo broke an embankment and swept away the enemy is difficult to regard as established fact. The relevant passage of the *Samguk Sagi* does not mention the destruction of an embankment. A note in the Korean History Database examines the later tradition on which the flood attack theory is based. It questions both when the tradition arose and the feasibility of constructing such an embankment.\n\nA battle using the river must therefore be distinguished from a flood attack carried out by breaking an embankment. The former is confirmed by the record of an attack during the river crossing. The latter is an interpretation that requires separate evidence.\n\n## Why do the same numbers appear in several historical works?\n\nEven when the same figure appears in multiple historical works, it cannot necessarily be treated as independent testimony. Later historical works may have quoted earlier books. A note in the Korean History Database explains the relationship between passages in the *Samguk Sagi* and the *Zizhi Tongjian*. It states that some content was omitted or quoted with changes in wording.\n\nThe accuracy of a number should therefore not be judged simply by counting the historical works in which it appears. The source from which the same figure was transmitted must also be examined. This makes it possible to assess the battle's outcome separately from the accuracy of its troop statistics.\n\n## What the Battle of Salsu means today\n\nThe Battle of Salsu shows that troop strength alone cannot explain the outcome of a war. When supplies are cut off, even a large force has difficulty continuing operations. Command decisions and fortress defenses also change the conditions of battle. The final attack during the river crossing was connected to the events that preceded it.\n\nIn studying history, the following points should be distinguished.\n\n- War and battle: the entire Goguryeo-Sui War and the 612 Battle of Salsu\n- Whole and part: the Sui expeditionary force and the nine armies advancing toward Pyongyang\n- Record and reconstruction: the attack described in historical sources and the later story of a flood attack\n- Event and compilation: the battle in 612 and a historical work compiled during the Goryeo period\n\n## Frequently asked questions\n\n### Where is the Salsu River today?\n\nThe Salsu River is generally identified as today's Chongchon River. Our History Net and the Encyclopedia of Korean Culture give this explanation. However, identifying the river does not establish the exact location of the crossing at the time.\n\n### Are Eulji Mundeok's birth and life known?\n\nEulji Mundeok's birth and death dates are unknown. The *Samguk Sagi* also states that his family background is unknown. Accounts of his birthplace in later books are of uncertain accuracy. Related information is summarized in the [Encyclopedia of Korean Culture entry on Eulji Mundeok](https://encykorea.aks.ac.kr/Article/E0042969).\n\n### Do “Sui forces” and “navy” mean the same thing?\n\nIn this article, “Sui forces” means the military forces of the Sui dynasty. Depending on the context, “navy” refers to forces that fight aboard ships. Lai Hu'er's navy must be distinguished from the land forces of Yu Zhongwen and Yuwen Shu.\n\n### Can the date of the Battle of Salsu be used as a Gregorian calendar anniversary?\n\nA lunar-calendar record should not simply be used as a Gregorian calendar anniversary. The Korean History Database dates the battle to the seventh lunar month of 612. This article does not convert it to a Gregorian date.","content_html":"\u003cp\u003eThe Battle of Salsu was a battle in 612 in which Goguryeo repelled an invasion by the Sui dynasty. Eulji Mundeok lured the enemy deep into Goguryeo territory, then attacked as it crossed the Salsu River during its retreat. It is remembered as a victory that thwarted a large expeditionary force's assault on Pyongyang.\u003c/p\u003e\n\u003cp\u003eThis article follows the \u003cem\u003eSamguk Sagi\u003c/em\u003e in the Korean History Database and was checked in September 2026.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#when-and-where-did-the-battle-of-salsu-take-place\" class=\"anchor\" id=\"when-and-where-did-the-battle-of-salsu-take-place\"\u003e\u003c/a\u003eWhen and where did the Battle of Salsu take place?\u003c/h2\u003e\n\u003cp\u003eThe Battle of Salsu took place in the seventh lunar month of 612, the 23rd year of King Yeongyang's reign. The Salsu River is generally identified as today's Chongchon River. The Goguryeo commander was Eulji Mundeok. His opponents were the Sui forces advancing toward Pyongyang under Yu Zhongwen, Yuwen Shu, and others.\u003c/p\u003e\n\u003cp\u003eThis battle was one part of the war between Goguryeo and Sui. The entire Sui army did not gather and fight at a single location on the Salsu River. The troops attacking Liaodong Fortress must be distinguished from those heading toward Pyongyang. Basic information about the battle is available in the \u003ca href=\"https://encykorea.aks.ac.kr/Article/E0026415\"\u003eEncyclopedia of Korean Culture entry on the Battle of Salsu\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#background-to-the-sui-invasion\" class=\"anchor\" id=\"background-to-the-sui-invasion\"\u003e\u003c/a\u003eBackground to the Sui invasion\u003c/h2\u003e\n\u003cp\u003eThe war arose from a conflict between the two states over the East Asian order. Sui unified China in 589. It then sought to expand its influence over neighboring states. Goguryeo sought to preserve its existing independent sphere of influence.\u003c/p\u003e\n\u003cp\u003eIn 598, Goguryeo attacked Liaoxi first. Emperor Wen of Sui responded by sending an army, but the campaign failed. His successor, Emperor Yang of Sui, personally launched a campaign against Goguryeo in 612. This sequence is outlined in \u003ca href=\"https://contents.history.go.kr/front/kc/printViewPopup.do?levelId=kc_i100400\"\u003eOur History Net's explanation of the Goguryeo-Sui War\u003c/a\u003e.\u003c/p\u003e\n\u003cp\u003eGoguryeo faced multiple attacks that extended as far as its capital. The main Sui forces put pressure on the fortresses of Liaodong. Nine armies under Yu Zhongwen, Yuwen Shu, and others advanced toward Pyongyang. The Sui navy commanded by Lai Hu'er also approached by sea.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#timeline-from-the-invasion-to-the-retreat\" class=\"anchor\" id=\"timeline-from-the-invasion-to-the-retreat\"\u003e\u003c/a\u003eTimeline from the invasion to the retreat\u003c/h2\u003e\n\u003cp\u003eThe Battle of Salsu progressed from reconnaissance of the enemy camp to luring the enemy in and attacking it during its retreat. The months below follow the lunar calendar used in the historical sources. They have not been converted to Gregorian dates.\u003c/p\u003e\n\u003cdiv class=\"overflow-x-auto\"\u003e\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003ePeriod\u003c/th\u003e\n\u003cth\u003eEvent\u003c/th\u003e\n\u003cth\u003eSource\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003e589\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eSui unifies China\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003eOur History Net, “Goguryeo-Sui War”\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003e598\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eGoguryeo attacks Liaoxi and Emperor Wen of Sui's campaign fails\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003eOur History Net, “Goguryeo-Sui War”\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003e612\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eEmperor Yang of Sui launches a large-scale invasion of Goguryeo\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003eOur History Net, “Battle of Salsu”\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003eSixth lunar month of 612\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eEulji Mundeok conducts reconnaissance of the Sui camp\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003e\n\u003cem\u003eSamguk Sagi\u003c/em\u003e, “Biography of Eulji Mundeok”\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003eSeventh lunar month of 612\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eGoguryeo attacks the retreating Sui forces at the Salsu River\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003e\n\u003cem\u003eSamguk Sagi\u003c/em\u003e, “Biography of Eulji Mundeok”\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003e613\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eSui invades again but withdraws after Yang Xuangan's rebellion\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003eOur History Net, “Goguryeo-Sui War”\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Period\"\u003e614\u003c/td\u003e\n\u003ctd data-label=\"Event\"\u003eAfter another Sui invasion, the war ends with Goguryeo's request for peace\u003c/td\u003e\n\u003ctd data-label=\"Source\"\u003eOur History Net, “Goguryeo-Sui War”\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\u003c/div\u003e\n\u003ch2\u003e\n\u003ca href=\"#eulji-mundeoks-reconnaissance-and-luring-strategy\" class=\"anchor\" id=\"eulji-mundeoks-reconnaissance-and-luring-strategy\"\u003e\u003c/a\u003eEulji Mundeok's reconnaissance and luring strategy\u003c/h2\u003e\n\u003ch3\u003e\n\u003ca href=\"#what-did-he-learn-through-a-false-surrender\" class=\"anchor\" id=\"what-did-he-learn-through-a-false-surrender\"\u003e\u003c/a\u003eWhat did he learn through a false surrender?\u003c/h3\u003e\n\u003cp\u003eThe \u003cem\u003eSamguk Sagi\u003c/em\u003e explains that Eulji Mundeok visited the enemy camp to conduct reconnaissance. Under royal orders, he entered the Sui camp under the pretense of surrendering. His actual purpose was to examine the opposing army's strengths and weaknesses. This is stated in the \u003ca href=\"https://db.history.go.kr/common/compareViewer.do?levelId=sg_044r_0020_0040\u0026amp;type=ancient\"\u003ereconnaissance account in the “Biography of Eulji Mundeok”\u003c/a\u003e.\u003c/p\u003e\n\u003cp\u003eThe Sui commanders tried to capture Eulji Mundeok. However, Liu Shilong opposed this, and they let him return. Eulji Mundeok did not respond when they asked him to come back. The record states that he then crossed the Yalu River and returned.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#why-did-they-starve-despite-receiving-so-many-provisions\" class=\"anchor\" id=\"why-did-they-starve-despite-receiving-so-many-provisions\"\u003e\u003c/a\u003eWhy did they starve despite receiving so many provisions?\u003c/h3\u003e\n\u003cp\u003eThe supply problem arose from the gap between the amount of food issued and the troops' actual ability to carry it. The nine armies reportedly received 100 days' worth of food when they departed. The soldiers also had to carry weapons and other military supplies. There are records of soldiers burying food because they could not bear the heavy loads.\u003c/p\u003e\n\u003cp\u003eThe mere fact that food was issued therefore does not mean the supply effort succeeded. Enough food had to remain for the advance to Pyongyang. As the campaign continued, this condition broke down. The Encyclopedia of Korean Culture describes this as an operational constraint on the nine armies.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#why-did-they-pretend-to-lose-and-retreat\" class=\"anchor\" id=\"why-did-they-pretend-to-lose-and-retreat\"\u003e\u003c/a\u003eWhy did they pretend to lose and retreat?\u003c/h3\u003e\n\u003cp\u003eEulji Mundeok's retreat was a luring operation intended to draw the enemy deeper into Goguryeo territory. Our History Net describes the seven battles fought in one day as deliberate defeats. The Sui forces exhausted themselves even as they won the battles. The troops that eventually advanced to the vicinity of Pyongyang faced supply shortages and fatigue.\u003c/p\u003e\n\u003cp\u003eEulji Mundeok sent Yu Zhongwen a poem calling for an end to the war. However, the poem alone cannot be seen as the reason for the decision to retreat. The shortage of provisions and the difficulty of taking Pyongyang Fortress must also be considered. A related explanation appears in \u003ca href=\"https://contents.history.go.kr/mobile/kc/view.do?code=kc_age_10\u0026amp;levelId=kc_i101200\"\u003eOur History Net's account of the Battle of Salsu\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#the-turning-point-was-the-retreat-and-river-crossing-attack\" class=\"anchor\" id=\"the-turning-point-was-the-retreat-and-river-crossing-attack\"\u003e\u003c/a\u003eThe turning point was the retreat and river-crossing attack\u003c/h2\u003e\n\u003cp\u003eThe decisive turning point came when the Goguryeo forces continued to pressure the retreating enemy. Eulji Mundeok sent an envoy to propose surrender once again. He offered to arrange an audience between the Goguryeo king and the emperor if the Sui forces withdrew. The exhausted Sui commanders used this as a justification to retreat.\u003c/p\u003e\n\u003cp\u003eThe \u003cem\u003eSamguk Sagi\u003c/em\u003e's “Biography of Eulji Mundeok” describes the ensuing attack as follows.\u003c/p\u003e\n\u003cblockquote\u003e\n\u003cp\u003eEulji Mundeok sent out his troops, surrounded the enemy on all sides, and attacked.\u003c/p\u003e\n\u003c/blockquote\u003e\n\u003cp\u003eThe Sui forces moved while fighting in a square formation. A square formation was designed to defend against attacks from multiple directions. When about half of the troops had crossed the Salsu River, the Goguryeo forces attacked the rear guard. The record states that the collapse of the rear units spread to other units.\u003c/p\u003e\n\u003cp\u003eFrom a tactical perspective, units can easily become divided while crossing a river. This interpretation explains their vulnerability during the crossing. The historical source directly identifies the rear guard as the target of the attack. The evidence comes from the \u003ca href=\"https://db.history.go.kr/common/compareViewer.do?levelId=sg_044r_0020_0110\u0026amp;type=ancient\"\u003eaccount of the Battle of Salsu in the “Biography of Eulji Mundeok”\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#troop-figures-and-the-outcome-of-the-battle\" class=\"anchor\" id=\"troop-figures-and-the-outcome-of-the-battle\"\u003e\u003c/a\u003eTroop figures and the outcome of the battle\u003c/h2\u003e\n\u003cp\u003eThe figures in the \u003cem\u003eSamguk Sagi\u003c/em\u003e show the major defeat suffered by the nine armies that advanced toward Pyongyang. However, the difference between the number of departing troops and returning troops is not necessarily the number killed. The locations and counting scopes represented by the two figures must be distinguished.\u003c/p\u003e\n\u003cdiv class=\"overflow-x-auto\"\u003e\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eRecorded figure\u003c/th\u003e\n\u003cth\u003ePeriod and scope\u003c/th\u003e\n\u003cth\u003ePoints to note when interpreting\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Recorded figure\"\u003e1 million\u003c/td\u003e\n\u003ctd data-label=\"Period and scope\"\u003eFigure reported as the number mobilized for the Sui campaign in 612\u003c/td\u003e\n\u003ctd data-label=\"Points to note when interpreting\"\u003eNot the number of troops gathered at the Salsu battlefield\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Recorded figure\"\u003e305,000\u003c/td\u003e\n\u003ctd data-label=\"Period and scope\"\u003eStrength of the nine armies when they first crossed the Liao River in 612\u003c/td\u003e\n\u003ctd data-label=\"Points to note when interpreting\"\u003eStarting size of the force advancing toward Pyongyang\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Recorded figure\"\u003e2,700\u003c/td\u003e\n\u003ctd data-label=\"Period and scope\"\u003eNumber who returned to Liaodong Fortress after the defeat in 612\u003c/td\u003e\n\u003ctd data-label=\"Points to note when interpreting\"\u003eCannot be treated as the total number of survivors from the entire expeditionary force\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\u003c/div\u003e\n\u003cp\u003eThe first figure is given in Our History Net's account of the Battle of Salsu. (verified figure: 1,133,800 soldiers and twice that number of provisions carriers · source: contents.history.go.kr · checked 2026-09-23) The latter two figures come from the \u003cem\u003eSamguk Sagi\u003c/em\u003e's “Biography of Eulji Mundeok.” (verified figures: 305,000 troops in the nine armies that first crossed the Liao River, 2,700 who returned to Liaodong Fortress · source: db.history.go.kr · checked 2026-09-23) These records do not reveal the exact strength or losses of the Goguryeo forces.\u003c/p\u003e\n\u003cp\u003eThe Battle of Salsu sealed the failure of Sui's 612 campaign. Emperor Yang of Sui ultimately withdrew his army. However, Sui attacked Goguryeo again in 613 and 614. This victory therefore cannot be regarded as the immediate end of the entire war between the two states.\u003c/p\u003e\n\u003cp\u003eSui's fall is also difficult to explain through a single battle. Repeated campaigns increased the burden on the state. Large-scale civil engineering projects and internal rebellions also played a role. This background is described in Our History Net's explanation of the Goguryeo-Sui War.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#records-and-interpretations\" class=\"anchor\" id=\"records-and-interpretations\"\u003e\u003c/a\u003eRecords and interpretations\u003c/h2\u003e\n\u003ch3\u003e\n\u003ca href=\"#what-the-historical-source-directly-states\" class=\"anchor\" id=\"what-the-historical-source-directly-states\"\u003e\u003c/a\u003eWhat the historical source directly states\u003c/h3\u003e\n\u003cp\u003eThe \u003cem\u003eSamguk Sagi\u003c/em\u003e recounts the reconnaissance, luring operation, and attack during the retreat. However, it is not a report written at the scene in 612. It is a historical work compiled in Goryeo by Kim Busik and others in 1145. Its date of compilation is given in \u003ca href=\"https://contents.history.go.kr/mobile/kc/view.do?levelId=kc_r200340\"\u003eOur History Net's explanation of the \u003cem\u003eSamguk Sagi\u003c/em\u003e\u003c/a\u003e.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#the-commonly-accepted-explanation\" class=\"anchor\" id=\"the-commonly-accepted-explanation\"\u003e\u003c/a\u003eThe commonly accepted explanation\u003c/h3\u003e\n\u003cp\u003ePublic history resources identify the luring operation and supply difficulties as key factors in the outcome. This explanation is shared by Our History Net and the Encyclopedia of Korean Culture. The ability of Liaodong's fortresses to hold out must also be considered. Eulji Mundeok's strategy can be understood within the broader conditions of the war.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#is-the-flood-attack-theory-a-confirmed-fact\" class=\"anchor\" id=\"is-the-flood-attack-theory-a-confirmed-fact\"\u003e\u003c/a\u003eIs the flood attack theory a confirmed fact?\u003c/h3\u003e\n\u003cp\u003eThe claim that Goguryeo broke an embankment and swept away the enemy is difficult to regard as established fact. The relevant passage of the \u003cem\u003eSamguk Sagi\u003c/em\u003e does not mention the destruction of an embankment. A note in the Korean History Database examines the later tradition on which the flood attack theory is based. It questions both when the tradition arose and the feasibility of constructing such an embankment.\u003c/p\u003e\n\u003cp\u003eA battle using the river must therefore be distinguished from a flood attack carried out by breaking an embankment. The former is confirmed by the record of an attack during the river crossing. The latter is an interpretation that requires separate evidence.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#why-do-the-same-numbers-appear-in-several-historical-works\" class=\"anchor\" id=\"why-do-the-same-numbers-appear-in-several-historical-works\"\u003e\u003c/a\u003eWhy do the same numbers appear in several historical works?\u003c/h2\u003e\n\u003cp\u003eEven when the same figure appears in multiple historical works, it cannot necessarily be treated as independent testimony. Later historical works may have quoted earlier books. A note in the Korean History Database explains the relationship between passages in the \u003cem\u003eSamguk Sagi\u003c/em\u003e and the \u003cem\u003eZizhi Tongjian\u003c/em\u003e. It states that some content was omitted or quoted with changes in wording.\u003c/p\u003e\n\u003cp\u003eThe accuracy of a number should therefore not be judged simply by counting the historical works in which it appears. The source from which the same figure was transmitted must also be examined. This makes it possible to assess the battle's outcome separately from the accuracy of its troop statistics.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#what-the-battle-of-salsu-means-today\" class=\"anchor\" id=\"what-the-battle-of-salsu-means-today\"\u003e\u003c/a\u003eWhat the Battle of Salsu means today\u003c/h2\u003e\n\u003cp\u003eThe Battle of Salsu shows that troop strength alone cannot explain the outcome of a war. When supplies are cut off, even a large force has difficulty continuing operations. Command decisions and fortress defenses also change the conditions of battle. The final attack during the river crossing was connected to the events that preceded it.\u003c/p\u003e\n\u003cp\u003eIn studying history, the following points should be distinguished.\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003eWar and battle: the entire Goguryeo-Sui War and the 612 Battle of Salsu\u003c/li\u003e\n\u003cli\u003eWhole and part: the Sui expeditionary force and the nine armies advancing toward Pyongyang\u003c/li\u003e\n\u003cli\u003eRecord and reconstruction: the attack described in historical sources and the later story of a flood attack\u003c/li\u003e\n\u003cli\u003eEvent and compilation: the battle in 612 and a historical work compiled during the Goryeo period\u003c/li\u003e\n\u003c/ul\u003e\n\u003ch2\u003e\n\u003ca href=\"#frequently-asked-questions\" class=\"anchor\" id=\"frequently-asked-questions\"\u003e\u003c/a\u003eFrequently asked questions\u003c/h2\u003e\n\u003ch3\u003e\n\u003ca href=\"#where-is-the-salsu-river-today\" class=\"anchor\" id=\"where-is-the-salsu-river-today\"\u003e\u003c/a\u003eWhere is the Salsu River today?\u003c/h3\u003e\n\u003cp\u003eThe Salsu River is generally identified as today's Chongchon River. Our History Net and the Encyclopedia of Korean Culture give this explanation. However, identifying the river does not establish the exact location of the crossing at the time.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#are-eulji-mundeoks-birth-and-life-known\" class=\"anchor\" id=\"are-eulji-mundeoks-birth-and-life-known\"\u003e\u003c/a\u003eAre Eulji Mundeok's birth and life known?\u003c/h3\u003e\n\u003cp\u003eEulji Mundeok's birth and death dates are unknown. The \u003cem\u003eSamguk Sagi\u003c/em\u003e also states that his family background is unknown. Accounts of his birthplace in later books are of uncertain accuracy. Related information is summarized in the \u003ca href=\"https://encykorea.aks.ac.kr/Article/E0042969\"\u003eEncyclopedia of Korean Culture entry on Eulji Mundeok\u003c/a\u003e.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#do-sui-forces-and-navy-mean-the-same-thing\" class=\"anchor\" id=\"do-sui-forces-and-navy-mean-the-same-thing\"\u003e\u003c/a\u003eDo “Sui forces” and “navy” mean the same thing?\u003c/h3\u003e\n\u003cp\u003eIn this article, “Sui forces” means the military forces of the Sui dynasty. Depending on the context, “navy” refers to forces that fight aboard ships. Lai Hu'er's navy must be distinguished from the land forces of Yu Zhongwen and Yuwen Shu.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#can-the-date-of-the-battle-of-salsu-be-used-as-a-gregorian-calendar-anniversary\" class=\"anchor\" id=\"can-the-date-of-the-battle-of-salsu-be-used-as-a-gregorian-calendar-anniversary\"\u003e\u003c/a\u003eCan the date of the Battle of Salsu be used as a Gregorian calendar anniversary?\u003c/h3\u003e\n\u003cp\u003eA lunar-calendar record should not simply be used as a Gregorian calendar anniversary. The Korean History Database dates the battle to the seventh lunar month of 612. This article does not convert it to a Gregorian date.\u003c/p\u003e\n","tags":["Goguryeo","Historical interpretation"],"faqs":[{"question":"When did the Battle of Salsu take place?","answer":"The Battle of Salsu took place in the seventh lunar month of 612, the 23rd year of the reign of King Yeongyang of Goguryeo. This date must not be converted to and written as July in the solar calendar."},{"question":"Where did the Battle of Salsu take place?","answer":"Salsu is generally considered to be the present-day Cheongcheon River. The location of the river must be distinguished from the exact crossing point at the time."},{"question":"Why did Eulji Mundeok feign surrender?","answer":"The Samguk sagi explains that the purpose of his visit to the enemy camp was to assess the strengths and weaknesses of the Sui army. His subsequent offer to surrender through an envoy is linked to the Sui army's decision to withdraw."},{"question":"How did Eulji Mundeok's strategy of luring the enemy work?","answer":"The Goguryeo army pretended to be defeated and retreated, luring the Sui army deep into its territory. The advancing troops faced food shortages and exhaustion. During their withdrawal, they were pursued by the Goguryeo army."},{"question":"Was the Battle of Salsu a flood attack carried out by breaching an embankment?","answer":"The claim that an embankment was breached is difficult to regard as an established fact. The Samguk sagi records that the rear guard was attacked when the Sui army was halfway across the river."},{"question":"What does the record that only 2,700 out of 305,000 returned mean?","answer":"In the Samguk sagi, the 305,000 were the troops of the nine armies that crossed the Liao River. The 2,700 were those who returned to Liaodong Fortress after the defeat. The entire difference between the two figures cannot be counted as soldiers killed in action."},{"question":"Did the Battle of Salsu end the war between Goguryeo and Sui?","answer":"Although the 612 campaign failed, Sui invaded again in 613 and 614. The Battle of Salsu must be distinguished from the end of the entire war between the two states."},{"question":"Have Eulji Mundeok's year of birth and place of origin been confirmed?","answer":"The years of Eulji Mundeok's birth and death are unknown. The Samguk sagi states that his lineage is unknown. Accounts of his place of origin in later records are also difficult to regard as established fact."}],"sources":[{"url":"https://db.history.go.kr/common/compareViewer.do?levelId=sg_044r_0020_0040\u0026type=ancient","title":"National Institute of Korean History, Korean History Database, Samguk Sagi, Eulji Mundeok Spies on the Strengths and Weaknesses of the Sui Camp","type":"source"},{"url":"https://db.history.go.kr/common/compareViewer.do?levelId=sg_044r_0020_0110\u0026type=ancient","title":"National Institute of Korean History, Korean History Database, Samguk Sagi, Eulji Mundeok Wins a Great Victory at Salsu and Notes","type":"source"},{"url":"https://contents.history.go.kr/mobile/kc/view.do?code=kc_age_10\u0026levelId=kc_i101200","title":"National Institute of Korean History, Our History Net, Chronology of Korean History, Battle of Salsu","type":"source"},{"url":"https://contents.history.go.kr/front/kc/printViewPopup.do?levelId=kc_i100400","title":"National Institute of Korean History, Our History Net, Chronology of Korean History, Goguryeo-Sui War","type":"source"},{"url":"https://contents.history.go.kr/mobile/kc/view.do?levelId=kc_r200340","title":"National Institute of Korean History, Our History Net, Chronology of Korean History, Samguk Sagi","type":"source"},{"url":"https://encykorea.aks.ac.kr/Article/E0026415","title":"Academy of Korean Studies, Encyclopedia of Korean Culture, Battle of Salsu","type":"source"},{"url":"https://encykorea.aks.ac.kr/Article/E0042969","title":"Academy of Korean Studies, Encyclopedia of Korean Culture, Eulji Mundeok","type":"source"}],"images":[{"id":1472,"url":"https://injoys.com/rails/active_storage/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6MjE0MDgsInB1ciI6ImJsb2JfaWQifX0=--e4e7e6a542cd0912236dbe5e131d4db03a148002/ai-7f340824.webp","is_representative":false,"generation_method":"ai_semi","license":"ai_generated","mime_type":"image/webp","width":1536,"height":1024,"translations":{"ko":{"alt":"강가의 수나라 군영에서 보급품과 말 사이를 호위받으며 걷는 고구려 사신 을지문덕","caption":"을지문덕은 거짓 항복으로 적진을 살핀 뒤 수나라군을 유인했다.","description":null},"en":{"alt":"Goguryeo envoy Eulji Mundeok escorted through a riverside Sui camp filled with supplies and horses","caption":"Eulji Mundeok used a false surrender to scout the enemy camp before luring the Sui army onward.","description":null},"ja":{"alt":"川辺の隋軍陣営で物資や馬の間を護衛されて進む高句麗の使者、乙支文徳","caption":"乙支文徳は偽りの降伏で敵陣を探った後、隋軍を誘い込んだ。","description":null},"es":{"alt":"El enviado de Goguryeo Eulji Mundeok escoltado por un campamento sui junto al río","caption":"Eulji Mundeok fingió rendirse para inspeccionar el campamento enemigo y después atraer al ejército sui.","description":null},"id":{"alt":"Utusan Goguryeo Eulji Mundeok dikawal melintasi perkemahan Sui di tepi sungai","caption":"Eulji Mundeok berpura-pura menyerah untuk mengintai kubu musuh sebelum memancing pasukan Sui.","description":null},"pt":{"alt":"O emissário de Goguryeo Eulji Mundeok escoltado por um acampamento sui à beira do rio","caption":"Eulji Mundeok simulou rendição para sondar o campo inimigo antes de atrair o exército sui.","description":null},"zh-hant":{"alt":"高句麗使者乙支文德在河畔隋軍營地中受護送，周圍遍布軍需與馬匹","caption":"乙支文德以詐降探查敵營，隨後誘引隋軍深入。","description":null},"de":{"alt":"Goguryeo-Gesandter Eulji Mundeok wird durch ein Sui-Lager am Fluss eskortiert","caption":"Eulji Mundeok täuschte seine Kapitulation vor, kundschaftete das feindliche Lager aus und lockte das Sui-Heer weiter.","description":null}}},{"id":1473,"url":"https://injoys.com/rails/active_storage/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6MjE0MTQsInB1ciI6ImJsb2JfaWQifX0=--3948d79169c3ca7abe14348930f17bb1946d6551/ai-eed5fed6.webp","is_representative":false,"generation_method":"ai_semi","license":"ai_generated","mime_type":"image/webp","width":1536,"height":1024,"translations":{"ko":{"alt":"살수를 건너는 수나라 퇴각군과 강가에서 방진을 친 후군을 향해 산비탈을 내려오는 고구려군","caption":"고구려군은 퇴각하던 수나라군이 살수를 반쯤 건넜을 때 후군을 공격했다.","description":null},"en":{"alt":"Goguryeo troops descend wooded slopes toward the Sui rear guard as the retreating column crosses a shallow river","caption":"Goguryeo attacked the rear guard when the retreating Sui army was halfway across the Salsu.","description":null},"ja":{"alt":"浅い川を渡る隋の退却軍と岸辺で防御陣を組む後軍へ、山腹から迫る高句麗軍","caption":"高句麗軍は、退却する隋軍が薩水を半ば渡った時に後軍を攻撃した。","description":null},"es":{"alt":"Tropas de Goguryeo bajan por laderas boscosas hacia la retaguardia sui mientras la columna cruza un río","caption":"Goguryeo atacó la retaguardia cuando el ejército sui en retirada había cruzado la mitad del Salsu.","description":null},"id":{"alt":"Pasukan Goguryeo menuruni lereng berhutan menuju barisan belakang Sui yang mundur menyeberangi sungai dangkal","caption":"Goguryeo menyerang barisan belakang ketika pasukan Sui yang mundur baru separuh menyeberangi Salsu.","description":null},"pt":{"alt":"Tropas de Goguryeo descem encostas arborizadas rumo à retaguarda sui enquanto a coluna atravessa um rio raso","caption":"Goguryeo atacou a retaguarda quando o exército sui em retirada estava a meio da travessia do Salsu.","description":null},"zh-hant":{"alt":"隋軍撤退隊伍渡過淺河，高句麗軍從林木覆蓋的山坡逼近岸邊結陣的後軍","caption":"高句麗軍趁撤退的隋軍渡過薩水一半時攻擊其後軍。","description":null},"de":{"alt":"Goguryeo-Truppen steigen bewaldete Hänge zur Nachhut der Sui hinab, während der Rückzug einen flachen Fluss quert","caption":"Goguryeo griff die Nachhut an, als das abziehende Sui-Heer den Salsu zur Hälfte überquert hatte.","description":null}}}],"published_at":"2026-09-23T13:07:21+09:00","updated_at":"2026-09-23T13:07:21+09:00","license":"cc_by","translation_status":"reviewed","available_locales":["ko","en","ja","es"],"data_locales":["ko","en","ja","es","id","pt","zh-hant","de"],"url":"https://injoys.com/en/articles/salsu-battle-612-eulji-mundeok-strategy-and-significance"}