Originally Posted by
beachfan
I heard I have to pick up bags in HND and schlep them to another terminal?
Since HND is your port of entry in Japan, you will have to pick up your luggage and take it through customs.
After customs, there should be a counter in the arrivals hall where you can check bags for your domestic flight. However, JAL's website says that it opens at 6:30 AM and it only accepts luggage up to one hour before departure, so you might do better to take your bags to the terminal for your domestic flight (Terminal 1 if it's JAL) and check them there.
https://www.jal.co.jp/jp/en/inter/airport/hnd/transit/