Mushroom Day (Kinoko no Hi)

What Is Mushroom Day?

October 15 is "Mushroom Day" in Japan. It was established in 1995 (Heisei 7) by the Japan Special Forest Products Promotion Association. October is when demand for mushrooms rises and they are most widely sold in stores. It is also the season for wild mushrooms, mushroom hunting and autumn-leaf viewing. The 15th was chosen because the middle of the month is a relatively calm time, well suited to promoting mushrooms to consumers.

Mushrooms as the Forest's Decomposers

A mushroom is the part of a fungus that grows above ground to produce spores. The main body is a network of threads called mycelium, spread through soil and wood.

• Returning wood to soil: Wood contains lignin, a component that is hard to break down, but "white-rot fungi" such as shiitake can decompose it. Fungi play a major role in turning fallen trees and leaves back into soil.
• Living with trees: Some fungi, like matsutake, are "mycorrhizal" - they connect with the roots of living trees and exchange nutrients. This relationship is why matsutake are so hard to cultivate.

A History of Mushroom Cultivation

Shiitake cultivation in Japan is said to date back to the Edo period. At first, growers cut notches in logs and waited for spores to settle, but in the Showa era the method of inserting spawn plugs into logs spread, making cultivation reliable. Today, enoki, bunashimeji, maitake and many others are grown year-round in indoor facilities.

Mushroom Trivia

• Vitamin D from sunlight: Mushrooms contain ergosterol, which turns into vitamin D when exposed to ultraviolet light. It is often suggested to place dried shiitake gills-up in the sun before use.
• Umami synergy: Guanylate, the umami compound in dried shiitake, tastes much stronger when combined with glutamate from kombu. Japanese mixed dashi makes use of this pairing.
• Low in calories: Mushrooms are low in calories and contain dietary fiber, making them a handy way to add volume to meals.
• New materials: In recent years, packaging and leather-like materials made from mushroom mycelium have been under development.
• Beware of poisonous mushrooms: Some wild mushrooms closely resemble edible ones. Never eat mushrooms you have picked yourself unless you can identify them with certainty.

Ideas for Mushroom Day

• Make mixed rice or a hot pot with several kinds of mushrooms.
• Make dashi with dried shiitake and kombu and taste the difference.
• Take a walk in a park or forest and look for mushrooms growing on fallen trees and leaves (but don't pick and eat them).

Something to Remember on Mushroom Day

October 15 is a day to enjoy mushrooms as an autumn delicacy while also appreciating how fungi support the forest. Quietly turning fallen trees back into soil, mushrooms are unsung heroes of the forest's cycle. Why not add a dish of seasonal mushrooms to your table today?