Judging from the fact that the production of permanent magnets made of magnetite began in the age of the Sung Dynasty, the compass was already invented by that time and the term 'magnetic pointer' is seen in the navigation book written in the Eisho era, it is considered that Kenminsen sailed using a primitive compass.
宋(王朝)代には磁鉄鉱から永久磁石を作るようになり、羅針盤の発見も済んでおり、永正の航海書にも「磁石の針」との言及があることから、遣明船は原始的コンパスを利用した航海を行っていたと考えられる。