Bump with info on the Koei Pasogo:
The system came out in 1996 and all the software released for it appears to be different variations on the board game Go. The text on the bottom right of the box says it had a suggested retail price of 39,800 Yen which works out to about $375US at the time. Thats quite an expensive handheld. For comparisons sake, the Game Boy Pocket came out the same year for $89.99. Thats 4X the price. Id have to guess that is one of the main reasons it seemingly flopped.
Now for the back of the box. Ive translated some of the text and this is what I loosely come up with:
-AC adapter available seperately for 2400 yen
-Takes 6 AA batteries and they will last 20 hours
-Easy to use great for kids
-Large, easy to see 5.6″ LCD screen
-Its awesome and portable, take it wherever you go
-We promise/guarantee comfortable play
-Lots of software for Go fans
Carts are about the size of Game Boy carts but twice as thick:
According to the insert inside the game box, It looks like theres at least 8 different pieces of software available for it ranging from 5800 yen to 9800 Yen. The bottom 5 are in a bracket labeled games. I couldnt translate the top two brackets well so I dont know what they are but I think one of them might be instructional. A couple of the games could be teaching various game rules or play strategies. The game I have is in the second bracket and Its got tons of text and it seems to play itself so I think thats what it does.