上げ底

1. Origins, structure, and basic meaning

• Structure: 上げ底 is read as あげぞこ and means a raised or false bottom, or padding that makes contents or length appear greater.
• Basic usage: It applies both to the physical bottom of a box and to adding more photographs to pad the length of a book.

2. Common pitfalls and similar expressions

• A physical false bottom
  • A box's 上げ底 is a raised bottom that makes the contents look more plentiful than they are. Example: 菓子箱は上げ底で、中身が実際より多く見えた。
• Padding out length
  • 本を上げ底にする figuratively means padding a book, here by adding photographs. Example: 写真を増やして本を上げ底にする案は退けた。