What is the Japanese term for the summer solstice?

The Japanese term for the summer solstice is Geshi. Written 夏至, it literally refers to the point when summer has reached its peak, and it names both the astronomical event and the corresponding seasonal marker in the traditional East Asian calendar.

Japan inherited a system of 24 solar terms from China. These terms track the Sun’s position through the year rather than dividing time into equal calendar months. Geshi is one of those markers and usually falls around June 21 in Japan, although the exact date can vary slightly.

The answer is easy to confuse with Tōji, the winter solstice, or with Shunbun and Shūbun, the spring and autumn equinoxes. In modern Japanese, 夏至 may also appear in seasonal calendars, weather reports and discussions of traditional customs surrounding the longest day and shortest night.