Original suikoden the novel is chinese.. its one of the 4 classic fiction of Chinese Novels. Story is a historic fiction based off some historic events during the Sung Dynasty of China.

Despite their denial.. Japanese culture still is mainly based off chinese... so retelling and spin off this type of stories are quite common. Other examples... Journey to West, another one of the 4 classics... fantasy story involving the Monkey King... Son Goku... who can ride a cloud and have a staff that can change to anysize by his will. there are tons of anime , manga, video game that all somewhat based itself off this story or parts of it... other than the most well known.. dragonball series.