the japanese language education center once posted an average of 2000 study hours needed to pass the jlpt n2 language proficiency test. by this estimate, if studying two hours every day it would take about three years

• about the characters
• song lyrics "hataraku kuruma", kanji version
• study guide

• ideophones/mimetics/onomatopoeia
• jlpt n5, n4, n3, katakana words
• jouyou kanji that share at least two components
• similar kanji
• the 2136 jouyou kanji as of 2010 ordered by stroke count
• up to 5 frequent words for each of the jouyou kanji
• vocabulary for the movie "weathering with you" (first 15 minutes)

• hiragana stroke order, katakana stroke order
• introduction to japanese
• jtest4you jlpt listening excercises
• kanji lookup and fuzzy word search kanji stroke order and one-word meaning on hover. top 30000 words fuzzy search that finds words with similar pronunciation. online and offline usable
• rikaichamp shows translations on hover
• edewakaru-doshi transitive and intransitive verbs and more explained with pictures
• kanji bakuhatsu a map of kanji connected by shared components

• jisho online dictionary for english, japanese, romaji, kanji and components
• google translate
• weblio dictionary
• furigana.info shows how common or likely different readings of kanji words are
• learn japanese adventure lessons
• imabi free lessons
• satori reader reading and listening practice with contextual meaning on click/tap on words. artificial stories not clearly graded. in my opinion, readers should be jlpt n5 or n4 at least. explains grammatical items casually without much rigor and depth
• pass jlpt5 4 3 vocabulary
• anki is a spaced repetition flashcard software for mobile and desktop. only shows flashcards in increasing intervals, cant do much else to help with learning

• kana

  • wanakana.js convert from latin characters to kana on the example page of this code library
  • kana.pro website that quizzes you on kana with a helpful progression system
  • kana dojo android app. flashcards, quiz for learning kana and a character recognition game

• kanji

  • jōyō kanji official guide to kanji characters and their readings
  • reading japanese signs photo collection of japanese road/street/etc signs with text
  • kanji tree android app. grades knowledge, browse components, shows reading frequency, handwriting practice, includes offline dictionary, better than paid apps
  • jensechu/kanji writing practice sheets. with faded example and stroke order
  • suiren a map of kanji words connected by shared components
  • one kanji a day wallpaper set
  • kanjicards flashcards with example words
  • kanji memory game
  • jrpg, a game where you beat kanji demons

• data

  • jmdict dictionary, cc-by-sa-3.0. also jmdict-simplified, cc-by-sa-4.0
  • kanji alive language data, cc-by-4.0
  • kanji bakuhatsu source code source code
  • kanjidic2 kanji meanings, cc-by-sa-3.0
  • kanjivg kanji stroke order svg images
  • radkfile/kradfile radical to kanji mapping and the reverse