On Japanese keyboards, there is a Reconversion key beside the space bar, which when highlighting some Kanji in Japanese will allow you to convert it to different Kanji (shows a dropdown of options). Apparently this was at one point ctrl+1, or ctrl+2, but neither work for me now. Ideas?
There are some differences between MacOS 10.1 and MacOS 10.2 for "Reconversion" in Japanese IME pencel menu and short-cut keys, e.g. the correct short-cut for JA "Reconversion" on MacOS 10.2 should be "Control + 2", but not "Control + 1" on MacOS 10.1. "Control + 1" on MacOS 10.2 is assigned to a different function other than "Reconversion".