大豆

1. Origins, structure, and basic meaning

• Structure: 大豆 is read as だいず and is a noun for the soybean used to make foods such as tofu, miso, and soy sauce.
• Basic usage: Harvesting the crop appears in 大豆を収穫する, while a source ingredient appears in 大豆から作られる食品.

2. Common pitfalls and similar expressions

• Source marker から
  • The source-material relation appears in 大豆から作る or 大豆から作られる, with から marking what the food is made from.
• Difference from 豆
  • 豆 broadly covers beans and individual beans of many kinds, while 大豆 specifically identifies the soybean widely used as a food ingredient.