Japanese: Usually pick up a copy of Cyclesports each month. Ad-heavy, but has decent articles, listings of upcoming events, ads from local shops. Fewer "How to Pedal" articles than, say, Bicycle Club.
English: Subscribe to Velonews for good pro cycling coverage, though with a strong N. American focus (lots of US domestic news). The few issues of the UK version of Cycle Sport I've read have been very good (the US one is okay, too, but the UK is better, IMO.)