I use the Kanji Study Android app to look up new words in virtually all situations where I need to look up Japanese words, including when reading books, watching TV, speaking with Japanese people in real life, etc.

The app might be only suitable for Japanese learners who are at upper elementary levels or higher (JLPT N4 or higher). I found the information in this app to be too advanced when I was a total beginner of Japanese.

I believe this app is the very best app for serious study of Japanese, and is far superior than all other Android apps and iOS apps in this category. Other apps don't even come close in terms of the amount of information and the features of the app.

This app only exists on Android. So if you're an iOS-only user, perhaps you could consider getting another inexpensive used Android device to use this app.

As a dictionary

You can use Kanji Study like a dictionary. In many ways, it's better than many dictionaries because of the app generates internal links to all of the other kanji, vocabulary, and example sentences.

As an example, look at the screenshot below which was generated from all of the details for the kanji 壱. I specifically chose this example because it has fewer rows in each section. But many kanji have a lot more rows, with a lot more words and sentences.

Recommended Addon: Outlier Kanji Dictionary

Purchasing the Outlier Kanji Dictionary add-on(s) will add additional detailed kanji explanations to each kanji page. I've found the explanations to be crucial for understanding some of the history behind particular kanji radicals, which has made learning new kanji easier.

Recommended Addon: KLC Graded Reading Sets

With the Kanji Learner's Course (KLC) Graded Reading Sets add-on, all kanji and vocabulary pages in the app will display natural curated example sentences. All words in all example sentences can be looked up too.

Quick Launch

You can make it easier to launch Kanji Study search dialog by adding the Kanji Search widget to your home screen. This widget allows you to launch the dictionary look up screen with 1 tap.

As a rapid Anki note creator

If you have AnkiDroid installed too, you can create a new Anki note in the Kanji Study app by tapping the ⊕ button when viewing a word or sentence, which launches this modal:

Kanji Study will automatically create and use its own Anki Note type for the new Anki Notes it creates.

I usually create new Anki Notes like this for words and sentences that I want to remember. After creating the notes, you can then quiz yourself in AnkiDroid later.

See my other Anki post for more details about using Anki and AnkiDroid.

As a study and review tool

There are various kinds of study session you can launch for any set of kanji that you select.

1. Flashcard study:

2. Multiple choice quizzes:

3. Writing challenges:

4. Learn by reading:

I think these study sessions are good for when you have a small batch of kanji (around 10-20) that you want to review again and again over several days or weeks.

I find the "Writing challenges" and "Learn by reading" study sessions to be the most useful.

Writing challenges

There's various settings for the kinds of writing challenges you can do.

I tend to start with the easiest ones (the first option in each menu), and then work my way down, as I get more familiar with a particular kanji.

Guided Study

Recently, an additional paid SRS (Spaced Repetition Study) addon was added to the app. I purchased it, but I haven't used it much recently. That's mainly because:

1. I'm bad at remembering to use any kind of SRS system, not only this one.
2. I already have Anki setup.

It looks potentially useful though.