Otoshi-buta (Drop lid)
Drop lid
Japanese: 落とし蓋（おとしぶた）
A lid on miso surface distributing weight evenly and protecting the surface.
An inner lid placed directly on miso surface. Distributes pressing stone weight evenly and keeps surface flat.
Traditionally a round wooden board; sanitized plate or plastic lid also works. Typical setup: wrap, drop lid, weight. Choose slightly smaller than container inner diameter. Wet and alcohol-sanitize wooden lids before use. Warped lids allow air entry. Choose one with a flat surface contacting the miso. Even pressure creates a beautiful finish.