So for ASB induced reasons, Japan is allowed to keep Southern Korea as well as Taiwan/Formosa as national territories in the aftermath of the Second World War. Japan is still subject to similar occupational reconstructive policies by the Wallies and the Soviets still set up an, ostensibly at least, independent People's Republic of Korea.
So what effect does this have on the coming Cold War and domestic Japanese politics in particular? Does Japanese Korea basically end up as Northern Ireland during the Troubles on crack?
North Korea would invade the South as OTL, but Japan would join in the war too. This would lead to immediate US, Chinese, and Soviet full support, making the Korean War much larger than OTL.
The Reds will probably win, since the US barely held out against China originally, so full Soviet support should more than make up for Post-War Japan's contributions.
Let's not ignore the potential impact in the future TTL of South Korean and Taiwanese companies like BenQ, Foxconn, Samsung, Hyundai, LG, Doosan, Daewoo, and Lotte.
Keep in mind that's combined with Japanese companies like Toyota, Honda, Nissan, Mitsubishi, Kirin, Pilot, Pentel, Nintendo, Capcom, Sony, UNIQLO, and Bandai.