Where does “天神七代” come from?

天神七代 (Japanese) comes from Japanese 天神, from Middle Chinese 神.

天神七代 (Japanese): the Seven Generations of Heavenly Gods, including 国常立 of the first, 豊雲野 of the second, 埿土煮 and his sister 沙土煮 of the third, 角杙 and his sister 活杙 of the fourth, 大戸之道 and his sister 大戸之部 of the fifth, 面足 and his sister 綾惶根 of the sixth, and 伊弉諾 and his sister 伊弉冉 of the seventh

Definitions

the Seven Generations of Heavenly Gods, including 国常立 of the first, 豊雲野 of the second, 埿土煮 and his sister 沙土煮 of the third, 角杙 and his sister 活杙 of the fourth, 大戸之道 and his sister 大戸之部 of the fifth, 面足 and his sister 綾惶根 of the sixth, and 伊弉諾 and his sister 伊弉冉 of the seventh

Ancestry of “天神七代”, step by step

天神七代 traces back through two separate lines of ancestry.

via Japanese 天神

Step	Language	Word	Meaning
1	Japanese	天神	the Japanese gods of the heavens; a noble wearing...
2	Middle Chinese	神	—

via Japanese 七代

Step	Language	Word	Meaning
1	Japanese	七代	—

Every word from Middle Chinese 神 →Every word from Japanese 天神 →