The haiku is a Japanese poetic form that consists of three lines, with five syllables in the first line, seven in the second, and five in the third. The haiku developed from the hokku, the opening three lines of a longer poem known as a tanka. The haiku became a separate form of poetry in the 17th century.
These rules apply to writing haiku:
“The Old Pond” by Matsuo Bashō
An old silent pond
A frog jumps into the pond—
Splash! Silence again.
“Over the Wintry” by Natsume Sōseki
Over the wintry
Forest, winds howl in rage
With no leaves to blow.