Before the Sanpo War, other local powers in the Kyushu and the Chugoku regions received tosho (a bronze seal which was required for trading with Korea) and also practiced amicable relations with the Korean Dynasty, but after the Sanpo War, the trading rights placed only in the hands of the So clan, which allowed the clan to monopolize the Japan-Korea trade.
三浦の乱以前には、九州・中国地方の諸勢力も朝鮮王朝から図書を受け通交していたが、三浦の乱を境に通交権は宗氏に集中し、日朝貿易の独占が行われるようになる。