Historical materials contain many of words associated with water, such as 'water-drinking disease,' 'Buddhist ceremony for bridging Sagami-gawa River,' 'a curse of the God of Water and Rain,' and 'appearance of Emperor Antoku over the sea,' therefore it is said that Yoritomo died from drowning.
史料は「飲水の病」「相模川橋供養」「水神の祟り」「海上に現れた安徳天皇」など水を連想させる語が多く、溺れた事が死に繋がったのではと見る。