Info
What is YYK?
YYK is a website dedicated to providing easily accessible resources to study Japanese, and to keep your progress and manage your study and review schedule for you.

It was made to accommodate users of varying levels of Japanese proficiency. No matter if you are a total beginner or if you are in the middle of your Japanese study, or maybe looking for a new challenge.

Study progress in YYK is made up of two major components, kanji, and words. YYK will show you different word content based on the kanji you have already studied. The more kanji you learn, the more words will be in the pool for your word study. If you have already studied some kanji before using YYK, but would still like to learn words for them, you can mark them as studied. They will not clog your kanji study, but will still count towards your word study. You can change these settings at any time. If you wish to see words independently of kanji progress, there is an option for that, too. You decide how much you want to study or review. How many kanji, words or reviews per session? It's up to you.

Everything you study will be recorded in your user data and be available for review at the appropriate time. You don't have to worry about when to review or what to study. It is all done for you. You can focus entirely on the contents of your study.

Please refer to the course list to see more details about what you can find in YYK.
List of study courses:

This course features kanji and words that will most likely appear in the various levels of the JLPT. There are no official lists as to what the JLPT actually contains. The kanji of this course have been separated into levels based on online data of expected and past JLPT test contents. The vocabulary of this course has been separated into levels based on Jonathan Waller's JLPT resources.

Kanji are Chinese characters used to write most of the words in Japanese. The Japanese government has decided on 2136 so-called "jouyou" kanji. These kanji are the most commonly encountered and learned by all children in school. This course contains all of them, together with the most important words that use them.

This course can be studied to prepare for any level of JLPT, as well as study some common words. This course features content almost identical with the Jouyou course. It is recommended picking the one most suited for your study goals.

This course features all jouyou kanji and words written with them ordered by JLPT level and beyond. It does not feature any pure hiragana or katakana words, nor words that have kanji outside the 2136 jouyou kanji.

Since the JLPT is a common measurement of study progress, kanji and words are categorized by these levels. Study progress does not follow the JLPT levels, but the kanji progress.

Kanji are Chinese characters used to write most of the words in Japanese. The Japanese government has decided on 2136 so-called "jouyou" kanji. These kanji are the most commonly encountered and learned by all children in school. This course contains all of them, together with the most important words that use them.

This course features content almost identical with the JLPT course. It is recommended picking the one most suited for your study goals.

This course features kanji used for names of people, places, and so on. The names in this course have been taken from lists containing the most common Japanese family names and the top 10 male and female given names of the last 100 years.

Jinmeiyou kanji are kanji mostly used for names.

This course can be used to learn how to read names in Japanese. Many kanji in this course are not used in names included in the course.

This course features high-level kanji related to the Japanese kanji kentei test, in particular levels Pre-1 and 1. The ateji and yojijukugo in this course are most likely only a small amount of the actual amount required to pass this test. Many other aspects of kanji and Japanese are also tested. Kanji kentei is often abbreviated to kanken in Japanese.
Ateji are words where the kanji have been selected for their sound, rather than their meaning. This can often happen because the word was not originally Japanese.
Yojijukugo is a term often used for words consisting of four kanji, that have a deeper meaning than the meaning of their kanji.

This course will be updated with additional content in the future to give a closer approximation of what may appear in the test.

This course features radicals to be studied by themselves. The progress here is shared with all other courses containing radicals.
Radicals are one building block of kanji, and every kanji has one major radical to which group it belongs.
List of extra courses & extras:

This course is designed to help with studying the hiragana and katakana syllabaries. Test your knowledge with the kana quiz.
Hiragana and katakana are used to write Japanese. Especially hiragana are used to write readings of words written in kanji. A good knowledge of hiragana is recommended before studying any other Japanese.
Use the study sessions to familiarize yourself with the syllables and test your knowledge with the quizzes.

This course is designed to learn the readings and locations of all prefectures in Japan. Additional information include the capital city, the region and the island to which the prefecture belongs. Use the study session to familiarize yourself with the prefectures and test your knowledge with the quizzes.

This is a collection of all contents of all courses. All radicals, kanji and vocabulary can be found here. All items are linked to their respective associates. Radicals link to kanji, which link to radicals and vocabulary items, which link to kanji.
How to use YYK?
First things first, what are you expecting of your Japanese study?

If you are a complete beginner, check out the "Kana syllabaries" extra course to study the first two basic writing systems.

If you want to study for any given JLPT level, go to the JLPT course and pick your level. There is no need to start at the lowest, each level will assume you know the kanji and words of the previous level.

If you want to learn the most common kanji and words, but not necessarily for the JLPT, try out the "Jouyou" course.

If you want to learn about names and kanji used in names, try the "Jinmeiyou" course.

If you are up for a challenge, and want to learn some of the higher level kanji even most Japanese people can't read or write, visit to the "Kanji kentei" course.

If you are using one of the four courses that feature kanji and vocabulary together, here is how to use them:
You can decide how much you want to study per session. In general, only one study session is calculated per category per day. How much that session contains depends on your settings. Some courses have words that do not contain any kanji. These words can be studied right from the start. All other words require you to study, or mark as studied, the affiliated kanji first. For optimal study progress, it is recommended doing one kanji session and one word session per day, in that order. On the next day after your first study sessions, reviews will become available automatically. Reviews are the third recommended session per day. Review dates are calculated based on your own evaluation of the studied item. If you feel really confident about a certain kanji or word, the review will be available at a later date. This means that content that gives you more trouble is reviewed earlier and more frequently.

When you open a course, or, if you have already studied a bit, look at the index page, available content will be marked for you. The kanji for "new" will show you any newly available study sessions, and a number will show you any available review sessions, as well as how many reviews they contain.

In order to keep studying content, all you need to do is follow this pattern. You can check on your progress by looking at the statistics. You can change your settings at any time, should you feel that you are going too fast or too slow.

YYK only manages the study and review content. What you do with the content is up to you. Some people like to do everything in their heads, some people like to write everything down.
How does it work?
YYK uses the SuperMemo 2 algorithm to calculate the intervals between reviews of items in any given study course. Every time you review an item you will be asked to rate your own response on a scale from "I completely forgot this." to "That was easy!". The next review will be scheduled depending on the response. Spaced repetition works by showing you items before you forget them. YYK will collect your reviews and present them on the correct day, you never have to worry about when or what to review.