The Shūi Wakashū(拾遺和歌集?, "Collection of Gleanings"), often abbreviated as Shūishū, is the third imperial anthology of waka. It was compiled by Emperor Kazan in about 1005. Its twenty volumes contain 1,351 poems. The details of its publication and compilation are unclear.
The Shūishū was an expansion of Fujiwara no Kintō's earlier anthology, the Shūishō(拾遺抄?, "Selection of Gleanings"), compiled between 996 and 999. Until the early nineteenth century, it was mistakenly believed that the Shūishō was a selection of the best poems from the Shūishū, and so the former was more highly regarded.
The Shūi Wakashū is the first imperial anthology to include tan-renga(短連歌?, "short linked verse"), or waka composed by two poets - the earliest form of renga recorded.