Haiku/Senryu/Tanka

A haiku is a Japanese poem that consists of three lines with 17 syllables. The first line has five syllables, the second line has seven syllables, and the third line has five syllables. The lines don't rhyme. Many modern English-language haiku don't obsess over syllables and instead follow more of the spirt of haiku in more of a short, long, short structure. 

Haiku poems often focus on images from nature. They emphasize simplicity, intensity, and directness of expression. Haiku also include a "cutting word" (kireji) and often a seasonal reference (kigo). 

Senryu is the playful cousin of the haiku. While haiku reminisces about nature, senryu likes to poke a bit of fun at human nature and remind us we are mortal indeed. I do not differentiate here. You be the judge of which is which ;-)

Tanka moves the haiku form in a new direction by focusing on personal experience and adding two addition 7 syllable or long lines.