Which waka form is literally a long poem?

The waka form literally meaning “long poem” is Chōka.

Chōka is built from repeated 5-and-7-on phrases and ends with a final 5-7-7 sequence. Unlike the compact tanka, its length can vary considerably, allowing poets to develop narratives, praise rulers, commemorate public events, or express grief at a fuller scale.

Chōka was especially prominent in the Man’yōshū, Japan’s oldest surviving anthology of waka. Many chōka were followed by a hanka, or “envoy,” usually written in the shorter tanka pattern. This pairing helped summarize or emotionally complete the longer poem.

A common mix-up is treating “waka” and “tanka” as exact synonyms. In modern usage, waka often means tanka, but historically waka was a broader category that included chōka, katauta, sedōka, and bussokusekika. Chōka later declined, while tanka became the dominant waka form.