The descendants of WATANABE no Tsuna grew into a bushidan (warrior bands) called Watanabe-to Party, and since they located at seaports, scattered everywhere in Japan as Suigun (warriors battle in the sea) and became the toryo (leader) of the Suigun in the Seto Inland Sea.
渡辺綱の子孫は渡辺党と呼ばれる武士団に発展し、港に立地することから水軍として日本全国に散らばり、瀬戸内海の水軍の棟梁となる。