Long, thin white stems with tiny caps, usually sold vacuum-packed; mild and crunchy. Besides going into soups and hotpot, it is blanched or steamed and dressed with garlic and scallion, or grilled.
Hot pot wouldn't be complete without enoki mushrooms.
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金 (gold) + 针 (needle) + 菇 (mushroom) - long thin stems shaped like golden needles. Often nicknamed 'see-you-tomorrow mushroom' (明天见) in Chinese internet humor because it tends to pass through the digestive system intact.