Question: do us phones work in japan?
Answer: Not all US phones will work in Japan, but (as the Japan Guide suggests) most modern 3G and 4G phones do. Specifically, the phone needs to support 3G UMTS 2100 MHz, 3G CDMA2000 800 MHz, or LTE band 1. According to this blog post the iPhone 6 will have no problem working in Japan if it is unlocked.