Old Tanabata (one of the five seasonal festivals in the Edo period, which was taken place on the seventh of July) (July 7 [the old calendar]): 7+7=14, 14÷6=2, the remainder is 2 => sakigachi.
旧七夕（7月7日(旧暦)）：7+714,14÷62あまり2→先勝