WaniKani is a Japanese radicals, kanji, and vocabulary learning web app that uses mnemonics and SRS to make kanji learning simple.

Spaced repetition! "Designed to help you remember facts (such as words and phrases in a foreign language) as easily, quickly and efficiently as possible. To do this, it tracks how well you remember each fact, and uses that info to schedule review times.

"This site contains an ever-growing set of study guides and tutorials for both serious students and casual enthusiasts of the language of the sagas. I add new lessons periodically."

"10,000 entry dictionary for beginning/intermediate students."

From the Capital Community College Foundation.