Blue Oath (alternatively Blue Wars or Blue Vows) is a shipgirl-themed Chinese smartphone game released in China by Babeltime. A Japanese version has been published by ZephyrusGames, and is available on the Android and iOS Japanese app stores.
The game runs on Android, Apple iOS and Windows-based devices.
Gameplay is similar to Kantai Collection Arcade, although with both minor and major changes, such as an affection system (and allowing marriage at 100 affection instead of Level 99), Hot Springs for morale recovery, the ability to select damaged skins for the ship girls’ appearance and in-app purchases.