June 1st was the first day to open an icehouse in ancient Japan.
In old calendar, June 1st was the beginning day of summer. On the day, people started to prepare for coming harsh summer. The nobility purified themselves by eating the ice that had been stored in an icehouse during winter. Instead of ice, the public have started to eat ice-shaped rice cakes, Minazuki that means June. Its white triangular rice cakes (this part is ice) topped with red bean paste are slightly sweet and very delicious.
Another summer purification rite called “Nagoshi no Harae” starts from this day. Have you seen a big thatched ring in Shinto shrines in Japan? It is called Chinowa. Worshippers pass through it like drawing a figure 8 starting from left, then right and left again, then walk straight to the main shrine and pray.
After this “Chinowa Kuguri”, you may repel bad luck and receive 1,000-days-worth of fortune.