The age of Hikaru Genji in this chapter has become clear by counting backwards from his age, 39, which was suggested by the description that 'he will celebrate his 40th birthday ceremony next year' in the later chapter of Fuji no Uraba (Wisteria Leaves), and picking up various descriptions of time going by between them.
本帖での光源氏の年齢は、古くからずっと後の藤裏葉帖で「翌年40の賀を迎える」とする記述からこの時点の光源氏の年齢を39とし、そこからそこまでにあるさまざまな時間の経過を表す記述を拾い上げて逆算していくことにより明らかにされてきた。