クロスワード ZERO is a free crossword application designed for Japanese language learners. This app is available exclusively on iPhone and developed by Releasebase Inc. The app offers a convenient and straightforward interface, making it easy to play and enjoy.

One of the most significant features of this app is the automatic focus of input location, which makes it easier for users to type in their answers. The app also displays mistakes in red, making it easy for users to identify and correct them. Additionally, the app automatically saves the progress, ensuring that users can pick up from where they left off. The app is a great way to learn Japanese while having fun solving crossword puzzles.