While you might hear that the gogyohka is a short Japanese poem form and mistakenly conflate it with the extremely popular haiku, the two are not related. The gogyohka is a modern invention of the Japanese poet Enta Kusakabe (born 1938) and only has two simple rules. It is five lines long. Each line is one phrase.
The waka is a type of Japanese poem form consisting of a 5-7-5-7-7 syllable structure. The poet is generally expected to divide waka into two distinct sections, usually signified in English by a hard stop of some kind, such as a period or semi-colon. This division is between the first three lines and the final couplet.
The somonka is a type of Japanese poem that actually consists of two shorter poems called tanka, a brief 31-syllable form, with somonka usually being exchanged by lovers or between two poets. Generally speaking, the first tanka is a love poem to the second person and the second tanka is the lover’s response.
Senryu is a type of short Japanese poetry that is structurally similar to the haiku but focuses more on human nature than the seasons. More specifically, senryu is usually focused on the comedic aspects of humanity, with a special focus on irony, wit, and everyday situations.
Sedoka is a Japanese poem form consisting of two tercets that each have a 5-7-7 or sometimes 5-7-5 syllable structure. There’s quite a bit of disagreement among western sources as to what theming the poem is intended to have, but natural imagery and a concept of reflective thinking do seem to appear consistently.
The katuata, which some sources refer to as the katauta, is a Japanese half-poem intended to be a question for a lover. It uses a similar structure to the haiku, opting for a 5-7-7 or 5-7-5 syllable structure, being different mainly in its theming and intended purpose.
Zappai are a poem form that is similar to haikus but thematically distinct. Both use a 5-7-5 syllable structure, but zappai are distinctly humorous whereas haikus (traditionally) reference the seasons. Neither is to be confused with senryu, yet another 5-7-5 form with its own unique rules for theming.
A haibun is a prosimetric work that utilizes a combination of prose and haiku segments. A haibun may only have one of each or it may have alternating segments for as long as the writer so desires. The form has seen many iterations and is now an internationally recognized literary form.
The dodoitsu is a poem form from rural Japan originating in the late Edo Period. In Western execution, the poem is characterized as having a syllable structure of 7-7-7-5. The form is similar to the much more popular haiku, in that the syllable count is the primary metric, with no rhyme specific scheme or meter.
The mondo is a Japanese poetic form emerging from Zen student-master traditions. The poem ultimately consists of two verses, with one posing a question and the other answering, usually in 5-7-7 syllable structures.
The kouta is a brief Japanese verse form, usually consisting of four lines but sometimes five, that tends to celebrate the average person’s everyday life in song. It seems to have been at its most popular during the Muromachi era (roughly the 14th-16th centuries), but it still sees use in modern Japan.
The imayo is a poem form from 12th century Japan that was originally intended for song. It has since been adapted into a poem with four 12-syllable lines, each divided up into sections of seven and five syllables by a caesura. Despite its similarities to the haiku, the imayo is rarely mentioned in the western world.
A renga is a Japanese collaborative genre of poetry, in which multiple poets alternately contribute stanzas to the poem. The renga came into existence after two people started writing a tanka (a traditional short Japanese poem) together, and it became a favorite pastime even in ancient rural Japan.
A tanka is a short Japanese free verse consisting of 31 syllables. While they don’t necessarily rhyme, tankas follow a specific syllable pattern. Tanka literally means “short poem or song”, with themes that are usually about nature, seasons, and desires. Hence, tankas tend to evoke strong and powerful imagery.
Haikus are a short, unrhymed form of poetry that originates from ancient Japan. Although early haiku poem themes typically revolve around nature, it expanded its subject especially in the 19th century when writing haikus was revitalized.