Wikipedia
Xiazhi
The traditional East Asian calendars divide a year into 24 solar terms (節氣). Xiàzhì ( pīnyīn), Geshi ( rōmaji), or Haji ( romaja) is the 10th solar term, and marks the summer solstice. It begins when the Sun reaches the celestial longitude of 90° and ends when it reaches the longitude of 105°. It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 90°.