五月雨を 集めてはやし 最上（もがみ）川
Samidare wo atsumete hayashi Mogamigawa
the May rain
gathers to a rapid stream
by 松尾芭蕉(Matsuo Basho)
季語(Season word): May rain (summer)
The Mogami River is located in Yamagata Prefecture and is one of the three largest rapids in Japan, together with the Fuji and Kuma Rivers. This Haiku describes that the Mogami River is full of water and flowing at great speed, collecting the continuous May rain.
In Haiku, it is common to use seasonal words that are tied to the lunar calendar, which is more than one month different from the current calendar (Gregorian calendar). In the lunar calendar, May is the month that includes the summer solstice, which corresponds to late May to early July in the Gregorian calendar (the new calendar). Therefore, the “May rain” in this Haiku refers to the rain that falls during the current rainy season (June to July).