Koshian

Koshian (漉し餡, “strained paste”) is anko made by pushing cooked, sweetened azuki beans through a fine-mesh strainer or cloth to remove every skin and fragment, then kneading the result into a smooth, uniform paste. The straining step is genuinely labor-intensive, which is part of why koshian is often treated as the more refined, higher-effort of anko’s two main styles. Kanto-style sakuramochi is a well-known example of a sweet typically filled with koshian rather than tsubuan.