[This (e.g. what I just said)] is not a joke!
"janai" is the negative form of "da". Tae Kim explains this as "negative state-of-being". So "joudan janai" literally declares "joudan" to be not a joke. E.g. [something that was said before] is not a joke! This is serious!
Reminder 1: In []-brackets I provide additional information that's clear from context but not explicitly stated in words. In Japanese, lots of things that are clear from context are omitted.Reminder 2: Japanese also has words like "this" or "that", but they are usually omitted - especially when the context these words refer to is known.
Frequently asked questions
What is spaced repetition?
Spaced repetition is a study technique that schedules reviews right before you're likely to forget something. Cards you know well are shown less often; cards you struggle with come back sooner. It's the same underlying method Anki popularized, and the one Decks uses.
Is Decks free?
Yes — you get 20 new cards a day by default and 50 reviews a day on the free plan, enough for most study routines. Premium removes the review limit entirely, for heavier study loads.
Do I need an account to use Decks?
No. Decks works immediately with anonymous login — you can start studying without creating an account, and add one later from Settings if you want to sync across devices.
Can I make my own flashcards, not just use the curated decks?
Yes — unlimited decks and cards on any subject, alongside the curated language decks.
What languages does Decks support?
Decks ships curated decks for Japanese, Chinese, Spanish, and French, covering everything from writing systems (hiragana, katakana) to grammar (HSK, Tae Kim's guide) to vocabulary and full sentences. You can also build decks for any other language or subject.