Guyu

The traditional Chinese lunisolar calendar divide a year into 24 solar terms. Gǔyǔ, Kokuu, Gogu, or Cốc vũ is the 6th solar term. It begins when the Sun reaches the celestial longitude of 30° and ends when it reaches the longitude of 45°. It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 30°. In the Gregorian calendar, it usually begins around April 20 and ends around May 5.

Traditionally, Guyu marks the beginning of warmer temperatures and the onset of the rainy season, making it an important period for farmers to ensure a satisfactory harvest for the rest of the year.

Pentads
Each solar term can be divided into 3 pentads (候). They are: first pentad (初候), second pentad (次候) and last pentad (末候). Pentads in Guyu include:

China

 * First pentad: 萍始生, 'Duckweed begins to sprout'.
 * Second pentad: 鳴鳩拂其羽, 'Cuckoo shakes off wings'.
 * Last pentad: 戴勝降于桑, 'Hoopoe perches in mulberry trees'.

Japan

 * First pentad: Ashi hajimete shōzu (葭始生), 'Reed begins to bud'.
 * Second pentad: Shimo yamite nae izuru (霜止出苗), 'Frost ends and rice seedlings to grow'.
 * Last pentad: Botan hanasaku (牡丹華), 'Peony blooms'.