one

1. Origins, structure, and basic meaning

• Structure: 壱 represents the number one; its on-reading is いち.
• Basic usage: 壱 is a formal written form of the numeral one. It appears in examples involving receipt amounts or old banknotes.

2. Common pitfalls and similar expressions

• Two written forms of the same number
  • Writing 壱 in place of 一 still represents one.