Understand how ancient Japan’s early military weakness, agricultural limitations, and genocidal expansion shaped the rise of the shogunate and Japan’s unique path to militarism.👇
1. Agriculture and Military Power in East Asia
1.1. Why Japan Was Initially Weak in Warfare
In ancient times, military strength stemmed directly from agricultural productivity. Compared to the Korean Peninsula, Japan had lower early agricultural output due to less developed farming methods and harsher terrain. This meant weaker state power and less capacity to support large armies.
Korea, particularly the Baekje kingdom, acted as a civilizational donor to early Japan, transmitting farming techniques, writing, and governance structures. Japan lacked a strong native system and military identity at this stage, relying on imported knowledge and avoiding major warfare.
1.2. Geography, Productivity, and Inevitable Growth
However, once Japan developed enough to clear land and establish sustained agriculture, its larger landmass and favorable plains gave it long-term potential to surpass the Peninsula. Like the Mongols, who surged in strength after a period of grassland expansion, Japan’s future power became inevitable once foundational development was complete.
In the pre-industrial world, natural resources like fertile land, water, and livestock determined national power. Japan’s eventual rise was predictable once these variables aligned.
2. The Origins of Japan’s Military Culture
2.1. From Settlers to Conquerors: Yamato and the Genocide of the Ainu
The Yamato people—immigrants from Korea—entered Japan and encountered indigenous tribes (often referred to as Emishi or Ainu) who lived without structured agriculture or clothing. The Yamato viewed them as subhuman and systematically exterminated or enslaved them.
This process mirrors European colonization of the Americas. The Yamato regarded the Japanese archipelago as a frontier to be conquered, not integrated. The absence of philosophical concepts like empathy or human equality allowed for the violent birth of Japanese territorial identity.
2.2. Korea’s Contrast: Fusion Instead of Eradication
On the Korean Peninsula, invading tribes like the Yemaek integrated with native Han groups after prolonged resistance and negotiation. Harsh terrain and strong native adaptation made genocide infeasible. The result was a hybridized population—modern Koreans—that evolved to resist external influence while emphasizing cultural unity.
In contrast, Japan’s foundational experience was one of conquest, not compromise, shaping a fundamentally different view of warfare and society.
2.3. The Shogun: From Ethnic Cleansing to Supreme Commander
The title “Shogun” derives from Seii Taishogun —literally, "Commander-in-Chief of the Expedition Against the Barbarians." These “barbarians” were Japan’s indigenous people, whom the state sought to eliminate.
The role of the shogun was born not from foreign defense, but domestic conquest. The central government sent generals eastward to kill and drive out the Emishi. As the campaigns succeeded, the shogun became the de facto ruler of Japan, with military legitimacy rooted in genocide.
3. The Feudal War System and Internal Conflict
3.1. From External Expansion to Internal Struggle
Japan’s military system was built on conquest. The government called up regional lords and their armies, promising land from the defeated tribes. But once all the indigenous groups were defeated and land ran out, warlords began fighting each other for power.
This led to the Sengoku (Warring States) period, where figures like Oda Nobunaga and Takeda Shingen rose. Endless internal war was baked into Japan’s system from the beginning—a side effect of its origin in military conquest rather than civil governance.
3.2. Feudal Incentives and the Logic of War
Feudalism rewards land with loyalty. Once expansion halts, ambition turns inward. The end of the “Eastern expeditions” meant no new land to give. Samurai, having been trained as warriors with no peacetime role, sought power through constant civil war.
Japan’s future wars—including its invasions of Korea—were driven not just by ambition, but by a deeply embedded military logic: when the system has no external outlet, it self-destructs or explodes outward.
4. Why War with Korea Became Inevitable
4.1. The Imjin War as a Historical Certainty
Japan’s 1592 invasion of Korea (Imjin War) was not merely a result of Toyotomi Hideyoshi’s delusions. Once Japan reached agricultural and military maturity, war was an almost unavoidable next step. Any leader with enough power would have considered expansion—Hideyoshi simply acted on it first.
From Korea’s perspective, such an invasion was unthinkable. Previous Japanese raids were pirate-level (wokou) incursions, never full-scale wars. Hideyoshi’s mobilization of over 150,000 soldiers shocked Joseon officials, who had no precedent for “official” Japanese wars.
4.2. Misreading the Threat
Korean historians had never seen Japan wage a state-backed war. All past Japanese actions had been labeled "foreign disturbances", not “wars”. The result: complacency and initial defeat. Only rare precedents—like Japan aiding Baekje in the Battle of Baekgang—hinted at organized war, and those too ended in failure.
5. Conclusion: Japan’s Military Identity Was Not Inevitable, But Engineered
Ancient Japan was not naturally warlike. It began as a culturally dependent, agriculturally weaker society. Its military system was forged through the genocide of indigenous people and land-based feudal rewards. Over time, this created a warrior identity centered around conquest—first domestic, then foreign.
Understanding this history offers a more grounded explanation of Japan’s militarism. It wasn’t genetic or cultural destiny—it was historical conditioning born from resource struggle, ideological violence, and power consolidation. That insight allows us to move past nationalistic myths and toward deeper historical clarity.
