Case Closed: The Fist of Blue Sapphire, known as Detective Conan: The Fist of Blue Sapphire (名探偵コナン 紺青の拳（フィスト）, Meitantei Konan: Konjō no Fisuto) in Japan, is a 2019 Japanese animated mystery film. It is the twenty-third installment of the Case Closed film series based on the manga series of the same name by Gosho Aoyama, following the 2018 film Case Closed: Zero the Enforcer. The film was released on 12 April 2019.

This was the last Heisei-era Case Closed film, released weeks before the 2019 Japanese imperial transition. The setting of the film takes place in Singapore, most notably surrounding the Marina Bay Sands.

The film was the 4nd highest-grossing Case Closed films in Japan with mixed to positive reviews. Critics praised its visual effects, direction, and characters but criticized its plot and screenplay. It was the second highest-grossing Case Closed film with a worldwide box-office gross of $123 million.