You’re here because you finished RTK (Remembering The Kanji by James Heisig), can recognize and tell the meaning of the kanji, and are ready to go to the next step: read them.
One piece of advice: don’t try RTK2. As much as we love RTK and its revolutionary method to learn the kanji meanings, RTK2 is not even close to be as good as its predecessor.
Why is that? Because RTK2, like all other learning methods, commits the same mistake of not focusing on 1 thing at a time.
Let’s illustrate this by taking as example a very popular approach to learn the kanji readings: learn them by their frequency of use.
下 is the 82nd most frequent kanji, but trying to learn all of its readings at a time is extremely inefficient. Indeed:
iiKanji’s objective is to teach the readings of the jouyou kanji following the constraint of only providing 1 unknown piece of information at a time.
Besides, this order has been optimized to allow you to read as many Japanese words as possible as quickly as possible.
Look at the graph below:
This graph shows the corpus coverage (ie, the number of Japanese words you are able to read) based on the number of kanji readings you have learned. For example, learning 1000 kanji readings can allow you to read between 18% and 73% of all Japanese words, depending on the order in which you learn them. Indeed, it makes more sense to learn some very recurrent readings first and let the rare ones, like 下ろす, for the end.
In the graph above, we compare the efficiency of learning the jouyou readings following 4 different orderings of the kanji readings. The least efficient of them are learning the readings of the kanji following the order in RTK and following the order in which they are taught in Japanese schools. Learning the readings of the kanji based on the frequency of the kanji gives better results, but since the frequency of the readings is not taken into account here, some rare readings may end up being learned sooner than they should, as is the case for 下ろす, for example.
Finally, iiKanji’s optimized order gives the steepest curve: learn only 400 of the 4200 jouyou readings and you will be able to read almost half of all Japanese words! Well, be warned that being able to read them should actually be “potentially able to” read them, because Japanese word readings do not follow any rules. You will have to look up the reading if it’s the first time you encounter the word, but you will have the readings of each of its kanji in your head, so look it up once and never again!
Kanji have ON and KUN readings. Some readings (usually KUN) make a word by themselves, so they can be learned as they are. For example, 思う（おもう）is one reading of the kanji 思 and a word by itself, meaning “to think”.
But some readings (usually ON) must be combined with other kanji to form an actual word. They don’t have a meaning alone. For example, the reading シ for the kanji 思.
In this case, iiKanji uses an “anchor word” to let you remember this specific reading for this kanji, as it is very difficult to remember it as an isolated sound. But this “anchor word” is not just any word: it has been chosen so that it is the most frequent word that uses the reading and kanji you are trying to learn plus any kanji and reading learned so far. This way, everything but the kanji and reading learned with this flashcard are known to you, so you can focus on it.
Let’s be honest, learning flashcards one after another is extremely boring. To cope with this and make it a little more exciting, instead of testing you with a single and lonely word, we test you with a whole real world sentence containing the reading and kanji being learned with this flashcard. Following our “1 thing at a time” premise, the sentences we provide only contain kanji and readings you have already learned so far (though you might not know the meaning of some of the words they form). This makes it much more fun than just studying the readings or words alone, plus it allows you to revise previously learned readings.
"...I think this is a really helpful website and i enjoy using it a bit every day. I like the progress bar showing the percentage of known kanji as it provides good motivation to keep going. Keep up the excellent work!"
—Stephen K., by email
"Really great site! Enjoying it so far. I really like the sample sentences."
—mhaellix, kanji.koohii.com forum user
"I really enjoy the system. I think that this methodology is really good... I will definitely suggest iiKanji to a couple of friends studying Japanese in my class."
—Vale, iiKanji User