A free program for Android, by ブロードメディア株式会社　G-cluster.

The Achievement and Creative Power-Up Kit for 30th Anniversary of the History of the Simulation Game: Gold Tower is a free app that allows you to play as one of the samurai empires. Not only will you conquer other nations by war, but you will also enrich your nation, which will allow you to exercise more army. You can zoom in and out of the details, and switch between perspectives to see the beauty of the castle town and changing seasons as you progress.

There are tons of operations to perform and tons of ways to achieve your goals. You can do everything from controlling a small island to conquering a huge country. It is all up to you.