Senryu, a satiric and often humorous counterpart to haiku, emerged in mid-18th century Japan as a form of popular self-expression among the rising merchant class. Named after the poet and editor Karai Senryu, this genre focuses on human nature, social behavior, and everyday life rather than the seasonal themes central to haiku. Traditionally composed in a 5-7-5 syllabic structure, modern English-language senryu are often written in free style with fewer than 17 syllables. While frequently humorous, senryu can also capture serious aspects of human experience, including hardship and social issues. Unlike haiku, which encourages contemplation, senryu aims to evoke immediate recognition and amusement. Through its accessibility and sharp observations of human folly, senryu remains a widely appreciated poetic form that continues to evolve in both Japanese and English-language poetry.
John Han (Tue,) studied this question.