What are the meter-long cotton bags used when pressing sake called?

The meter-long cotton bags used when pressing sake are known as "saka bukuro." This term specifically refers to the traditional bags that hold the sake mash (koji, yeast, and steamed rice) during the pressing process to separate the liquid sake from the solid rice remains. The material and construction of these bags enable them to retain the sake mash while allowing for the free flow of liquid, facilitating the extraction of sake efficiently.

In contrast, "seimai buai" refers to the degree of rice polishing and is crucial for determining the quality of sake, but it is not related to the pressing process itself. "Sandan shikomi" is a method of multiple fermentation steps in sake production but does not indicate the physical equipment used for pressing. "Seishu" denotes refined sake, which has undergone a specific filtration and stabilization process after pressing, rather than being a tool or material used during the pressing stage. Thus, the association of "saka bukuro" with the pressing operation makes it the correct answer.