In fact, according to the record of the first Japanese envoy to the Sui Dynasty in China, which was not written in the Nihonshoki, but in the Suishu, the King of Wa took the Heavens and the Sun as brothers.
事実、『隋書』にあり『日本書紀』に記述がない第一回目の遣隋使（名前の記述なし）の記事には、倭国の倭王が天と日を兄と弟としていた（「俀王以天爲兄以日爲弟」）とある。