Before the Nintendo 64DD there was Morita Shogi 64!
Morita Shogi is a long running series beginning on the PC88 up until today with Morita Shogi on the Iphone. The unique thing with Morita Shogi 64 is that it houses a very compact modem by 1998 standards and I guess it might have been slated for 64DD but canned in the last minute.
Only in Japan can a game like Shogi be so popular that they will manufacture a game cart for the N64 with a modem, one can only wonder if it was financially profitable since N64 carts were expensive to produce to begin with if compared to a PS1 disc.
I don't know how long the internet service lasted but it is today discontinued so you can't play online with it anymore *sniff*.
Thanks to Jrra for sacrificing his pennies by buying this, cracking it open and taking pictures of it for our enjoyment :).
source: http:/emuconsoleexploitnews.blogspot.com