Kobayashi Issawas a Japanese poet and lay Buddhist priest of the Jōdo Shinshū sect known for his haiku poems and journals. He is better known as simply , a pen name meaning Cup-of-tea (lit. "one [cup of] tea"). He is regarded as one of the four haiku masters in Japan, along with Bashō, Buson and Shiki — "the Great Four."
Reflecting the popularity and interest in Issa as man and poet, Japanese books on Issa outnumber those on Buson and almost equal in number those on Bashō. Provided by Wikipedia