'The five seasonal days (sekku)'. After the 7th of the 1st month (nanakusa; seven herbs) these are respectively 3 March (3/3: Momo-no-sekku; Hina-matsuri), 5 May (5/5: Tango-no-sekku; kodomo-no-hi), 7 July (7/7: Tanabata) and 9 September (9/9: Kiku-no-sekku).
A Popular Dictionary of Shinto. Brian Bocking.