spine · mallet

1. Origins, structure, and basic meaning

• Structure: 椎 has 12 strokes and appears in words for the spine and in a mushroom name.
• Basic usage: 椎茸（しいたけ） means shiitake mushroom; 脊椎（せきつい） means the spine or vertebral column.

2. Common pitfalls and similar expressions

• Readings depend on the word
  • In 椎茸, 椎 is read しい; in 脊椎, it is read つい.
• Rehydrating dried food
  • 干した椎茸を水で戻して means rehydrating dried shiitake mushrooms in water and then continuing.
  • In this context, 戻して describes restoring moisture to dried food.