Like haiku, tanka developed in Japan but much earlier, about 1500 years ago.  Tanka in English are written in five short lines totaling 31 or fewer syllables.  The first and third lines contain five or fewer syllables, while the second, fourth and fifth lines have seven or fewer syllables.  Also like haiku, tanka use simple, unadorned language, compare or contrast a couple of images and strive for  heightened awareness.  In addition, there's an emphasis on states of mind, usually the poet's.  Often these feelings relate to the natural world, and undergo a subtle but significant change by the poem's end.  Lyrical and personal, tanka are perfect for expressing innermost thoughts and feelings, from serious to humorous.  To read some of the best tanka on the Internet, or anywhere else, visit Jane Reichhold's Tanka Splendor Contest web site at http://www.ahapoetry.com/TScontes.htm   There you'll find some of my winning tanka, such as these:

feeling cranky
the palm reader tells him
she's never seen
a life line
as short as his