China vs Japan

China is cheaper: $1,100/mo against Japan's $1,631/mo. China is pricier than 15 of 22 Asian countries; Japan is pricier than 19 of 22 Asian countries.

Japan is safer: 4.8/5 against China's 3.3/5. China is safer than 16 of 22 Asian countries; Japan is safer than 20 of 22 Asian countries.

Japan scores higher on mobility: 4.0/5 against China's 3.3/5. China is easier to get around than 16 of 22 Asian countries; Japan is easier to get around than 19 of 22 Asian countries.

China scores higher on culture: 3.5/5 against Japan's 3.3/5. China is richer in culture than 15 of 21 Asian countries; Japan is richer in culture than 12 of 21 Asian countries.

China's passport reaches 52 destinations visa-free to Japan's 122 — Japan opens more doors without a visa. Passport strength shifts over years of naturalisation, not months of planning, so it's a long-horizon footnote — not scored in the tally.

China is better connected: 755M passengers/yr against Japan's 289M passengers/yr. China is busier than 85 of 87 countries worldwide; Japan is busier than 82 of 87 countries worldwide. China sees ~53 air passengers per 100 residents a year; Japan sees ~2 air passengers per resident a year — a derived figure, not itself ranked.

China runs -10°C to 37°C for most people; Japan runs -10°C to 37°C for most people. Harbin runs colder, at -34°C; Hachinohe runs colder, at -25°C. Depends on you — which range fits your tolerance is the real question here, not a score.