Denchi no Nihongo is a mobile application designed to help users review and practice Japanese writing systems and vocabulary in a single, consolidated platform. The app covers hiragana, katakana, and kanji, and includes real practice exercises accessible from a smartphone. It originated from the observation that learners often had to switch between multiple applications to study different aspects of the language, and was built to offer a simple, daily review tool that centralizes study materials. The app is available for free on the Google Play Store. The application provides several core features. Users can study individual characters through flashcard-style cards that display the character alongside a mascot. Kanji learning is structured step by step, with cards showing the character, its reading, and translation (for example, 日本 shown as Nihon for Japan). All study material is organized in one location, including vocabulary, hiragana, katakana, kanji, and auditory exercises. Lessons are designed to be short and accessible, the interface is entirely in Spanish, and the app contains no invasive advertising. Typical use cases involve daily, brief review sessions where a learner opens the app to practice a set of characters or words. The workflow moves through study cards, listening exercises, and kanji step-by-step drills, allowing users to progress at their own pace. The app was developed through a process that included design with attention to detail, development, testing with a group of people in different roles, and eventual launch on the Play Store. The name Denchi (でんち, meaning battery in Japanese) reflects the concept of providing energy for studying Japanese.