実印(じついん)

Etymology

実(じつ) (real, actual) + 印(いん) (seal)

Literally "real seal" - the officially recognized seal.

USAGE (registration):
To make a seal your 実印(じついん), you must:
1. 印鑑登録(いんかんとうろく) - register it at your local 市区町村(しくちょうそん) office
2. You'll receive an 印鑑登録証(いんかんとうろくしょう) (registration card)
3. You can then obtain 印鑑証明書(いんかんしょうめいしょ) (seal certificate) as needed

USAGE (when it is needed):

• 不動産(ふどうさん)取引(とりひき) - real estate transactions
• 自動車(じどうしゃ)の購入(こうにゅう)/売却(ばいきゃく) - buying/selling cars
• 会社(かいしゃ)設立(せつりつ) - company establishment
• 保証人(ほしょうにん) - acting as guarantor
• 遺産(いさん)相続(そうぞく) - inheritance matters

USAGE (the seal itself):
実印(じついん) typically should be:

• Unique (not mass-produced)
• Larger than 認印(みとめいん) (usually 13.5-18mm)
• Made of durable material

Watch out

Never lend your 実印(じついん) to others - it can be used to enter into binding contracts in your name.