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The sijo is a Korean poetic form featuring three lines and usually preferring a 3.4.3.4. syllabic arrangement, with the final line usually being something like 3.5.4.3. For example, this poem:
Night falls on the mountain village; a dog barks from far afield.
Open the gate and behold -- the sky is cold and the Moon is out;
O dog, why bark at empty mountains, why at the dozing Moon?
The sijo is a much freer style of verse than the haiku, which I suppose could appeal more.