(keitai-l) Entering text on japanese phones?

Hi, Everyone!

I am new to this list. I work in a game company called TriggerDuck
Entertainment Engineering designing mobile games. I was just wondering
whether any one of you know how viable chatting is on japanese phones. I
remember hearing that it is so complicated to enter japanese character into
a phone that it is seldom done - but on the other hand I hear that people
compose mails and short messages using their phones, so it must be working
to some extent.

I am currently adapting one of our games for the japanese market and I need
to know whether I need to design around the chatting aspect. Anyone?

thanx a lot!

simen