"Great Kanji puzzle!" is an iPhone application developed by nullhouse LLC. It falls under the category of Education & Reference and is available for free. This program, called "読めないと恥ずかしい漢字" in Japanese, aims to test and improve your kanji skills while providing brain training in your spare time.

With over 500 questions to challenge yourself, this app offers a great opportunity to enhance your kanji knowledge. Its engaging mechanism ensures that you won't get bored while learning. Whether you are a beginner or an advanced learner, this game can help you strengthen your kanji power.

If you are looking for a fun and educational way to improve your kanji skills, "Great Kanji puzzle!" is definitely worth a try. Download it now and start your journey towards mastering the complex world of kanji characters.