Thank you for your clear explanation about renga so much. It is the first time for me to completely figure out what renga is and the relationship between Haiku and renga. Originally Haiku is the first verse of renga. And it seems that renga is a little similar to Chinese poetic couplet which usually only contains a pair of sentences. It can be written by the same person. Or one person composes the first line, the rest need to match an antithetical line, then select the best one among them. Till now, pasting spring couplet is still a popular kind of custom during the spring festival in China.

What's more, The description on autumn evening from the "The Pillow Book" is so familiar and cordial to me. It reminds me of a few classical wordings in ancient Chinese poetry: 寒鸦点点/crows in threes or fours and 雁字/formation of wild goose which I always loved reading before.