Just wanted to point out that this isn’t possible, in case anyone thinks that it is and is disappointed when they can’t go super fast.
Given how the SRS (Spaced Repetition System) works, there is a maximum possible speed at which it’s possible to progress on WaniKani; 6 days 20hours per level.
That maximum speed is because you can only progress to the next level when you’ve gotten the majority of kanji for the current level to Guru. When you level up, you get just over half of the kanji for that level unlocked and you must get these up to Guru before you unlock the rest for that level.
So if you look at the maths this way:
Note that these intervals are reduced by around 50% for level 1 and 2, so they’ll go faster
Unlock Kanji = 0hrs
Apprentice 1 -> 2 = 4hrs later
Apprentice 2 -> 3 = 8hrs after that
Apprentice 3 -> 4 = 23hrs after that
Apprentice 4 -> Guru = 47hrs after that
So the total levelling time for first batch = 3 days 10 hours
You then unlock the next batch and must spend 3 days 10 hours again on those