The script is here: Shin WaniKani Leech Trainer
Version 3.0
With the major version bump to 3.0, the script is now using a completely rewritten backend, rather than hitechbunny’s previous one. There may/will be bugs, but I’m pushing on with the rewrite as hosting the old one costs me money, and I wanted to learn some Go.
If you upgrade and see an enormous number of leeches, that’s because the information about what you had trained with the old system hasn’t been migrated. Presuming you were at zero leeches, there’s an option to “Squash My Leeches” from the browser bar which will reset you to zero. Leeches will then appear in the usual way (outlined below).
The other reset option is to wipe out all of your training data and start again. That’s under “XXX: DELETE MY STATS!”. If things are going horribly wrong, you could delete your stats to get back to all leeches, and then squash them all, and see if things improve. None of this will affect your WK data at all.
What does it do?
The script will put together a Quiz of 10 leeches. It will exclude any leech that is too recent (less than 24 hours since the last review), or too old (less than half the time between reviews remaining), or already trained. Any trained leech that is subsequently reviewed incorrectly goes back in the pool.
This is more of less what it looks like (this animation is slightly out of date):
Every leech is repeated 3 times in the lesson. To clear a leech you must get it right each time. Furthermore, the lesson will include items related to the leeches in your quiz. These might be visually similar kanji, or vocabulary using the same kanji. These are just there to spice things up a bit and don’t have any bearing on quiz results.
Leech training data is stored on the server-side. So you can switch browsers or computers without losing track of your progress.
As always bug reports and suggestions for improvements welcome. Enjoy!
PS This script steals heavily from the awesome [Userscript] Self-Study Quiz If you haven’t installed that script you should go ahead and do it now.