Japanese Territorial Expansion: Islands Controlled & Conquered (1875–1945)

Japan’s modern territorial history involves four home islands and dozens of acquired islands through colonization, treaties, and war (1875–1945). The term “conquered” applies to territories taken by force; others were annexed, leased, or mandated.

🏝️ The Four Home Islands (Not “Conquered”)

• Honshū (main island, Tokyo, 104M people)
• Hokkaidō (north, colonized 1869+; Ainu displacement)
• Kyūshū (southwest, Nagasaki, Fukuoka)
• Shikoku (between Honshū/Kyūshū)

These are the Japanese archipelago core—incorporated, not conquered.

🌊 Acquired/Controlled Islands (Chronological)

⚔️ WWII Expansion (1941–42) – Occupied, Not Annexed

• Philippines, Dutch East Indies (Indonesia), Malaya, Singapore, Borneo, Guam, Wake, Gilbert, Solomon, New Guinea, Aleutians (Attu, Kiska).
• All lost 1944–45.

📜 Postwar Settlement (1945–52)

• Treaty of San Francisco (1951): Japan renounces all claims to Korea, Taiwan, Kurils, Sakhalin, Spratlys, Paracels, Pacific Mandate.
• Retains: Four home islands + Ryukyus (returned 1972), Bonins, Volcano (Iwo), Senkakus (disputed), Liancourt (disputed).
• US Occupation (1945–52): Demilitarization, democratization.

🗺️ Current Disputes

• Kurils (Northern Territories): Japan claims Habomai, Shikotan, Kunashir, Iturup; Russia administers.
• Senkaku/Diaoyu: Japan administers; China (PRC) & Taiwan (ROC) claim.
• Liancourt/Takeshima/Dokdo: Korea administers; Japan claims.

Japan’s island empire was built by treaty, colonization, and conquest—and dismantled by WWII defeat. Today, it administers its home islands plus the Ryukyus, Bonins, and Volcano Islands, while three territorial disputes (Kurils, Senkaku, Liancourt) remain unresolved diplomatic flashpoints.