Tenka Tōitsu is a strategy game set in feudal Japan, and and the first title in SystemSoft's long-running strategy series. Remarkably similar to the better-known Nobunaga's Ambition, Tenka Tōitsu casts the player as a daimyo during the Sengoku (Warring States) period in Japanese history, the campaign starting in 1551 with Oda Nobunaga's rise to power. The presentation is far more straightforward compared to Koei's game, and there is a focus on strategic use of a small number of units, much like a game of chess. The player may only control a dozen or so units at any given time, and can order them to advance, retreat, and attack as necessary.
Description from MobyGames