Sorry, Chris, but the JGSDF does not use any AH-1Ws.
The current model that they use is the AH-1F, with the last one delivered to them in 2000. I also found an article online that says the Japanese gov't has long range plans to build the AH-64 Longbow in-country, and Boeing plans to deliver them their first Apache in 2006.
The only major players to use the AH-1W outside the US are Turkey and Taiwan. Sorry, I know that's not what you wanted to hear.
Cobrahistorian, correct me if I'm wrong on the international cobras, lol