Buna shimeji, also known as beech mushroom (Hypsizygus tessulatus), is an edible mushroom species native to East Asia, particularly Japan, China, and Korea. It typically grows on decaying beech trees, which is the origin of its common name. In culinary use, buna shimeji is prized for its firm texture and delicate, nutty flavor, becoming mildly sweet and less bitter after cooking.
The mushroom is commonly used in stir-fries, soups, hot pots, and other traditional East Asian dishes. Historically, it has been cultivated since at least the 20th century, and today it is also commercially produced in Europe and North America, both in white and brown varieties. It is typically sold in clusters and should be cooked before consumption, as raw shimeji mushrooms are considered unpalatable and difficult to digest.