Sengaku's work took place in four phases, in Kangen 4 (1246), Bun'ei 2), Bun'ei 3 and Bun'ei 10 (1265, 1266 and 1273 respectively), producing four textual lines called the "Kangen-bon", "Bun'ei Ninen-bon", "Bun'ei Sannen-bon" and "Bun'ei Jūnen-bon", named for the eras/years they were produced.