替え玉

1. Origins, structure, and basic meaning

• Structure: 替え玉(かえだま) means a stand-in for someone or an extra serving of noodles.
• Basic usage: Context distinguishes an additional restaurant order from someone taking another person's place.

2. Common pitfalls and similar expressions

• The food and person senses
  • 替え玉を一つ頼んだ means ordered one extra serving of noodles.
  • 試験で替え玉を使う means using a stand-in to take someone's place on an exam.