Game Boy Wars

" Game Boy Wars (ゲームボーイウォーズ?) is a turn-based war simulator produced by Nintendo and Intelligent Systems that was released for the Game Boy in Japan only in 1990. It is a portable follow-up to the 1988 Family Computer war simulator Famicom Wars, making it the second game in Nintendo's Wars series." Source: Wikipedia, "Game_Boy_Wars," available under the CC-BY-SA License.