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The most efficient way to remember the meaning and writing of Japanese characters.


Remembering the Kanji

Use your imaginative memory to remember thousands complex Japanese characters, with Remembering the Kanji by James W. Heisig.

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Try the sample chapter (includes 294 kanji).
Both the 5th and 6th editions are supported!

Review, Share and Improve!

See your progress Visualize your progress as stacks of flashcards. Reviews are automatically scheduled based on your past results.

Review the kanji Review the kanji online. Repeat more of the difficult characters, and less of those that you know well.

Share mnemonics Feeling stuck? Share stories with fellow learners. Find help and encouragement on the community forums!


Forum Upgrade!7 October 2015
The forum is finally being upgraded to a better platform (MyBB) that allows PMs (private messaging), reputation, likes and thanks, a rich text editor, video embedding inside posts (example), etc.

The forum can be previewed at foam.koohii.com (hah). Please note it's very much a work in progress. The colour scheme has been implemented but there is still a lot of work to customize the layout. I will try to make it more responsive and mobile friendly.

Please bookmark the NEW FORUM FEEDBACK / DISCUSSION forum and check back over the next couple weeks to help us out with feedback. Right now the most helpful would be your feedback on the forum features and plugins you would like to see, as well as look into old threads and let me know if you find any issues with the posts and threads (I've had to convert everything over to MyBB and solve various UTF-8 issues).

Please note the preview forum is temporary so do not spend much time editing older posts. There will be an additional, final conversion on the day we switch over, that will include all the latest activity from our live forum.

Database maintenance23 September 2015
The website was unavailable for ~15 mins today. I realized it's been a while since run the optimize functions on the database. It seems to have helped... though not by much.

The cache of the shared stories list is a good improvement, however it only saves one relatively expensive query. There is another similar query for the "Recent Stories" that is not cached yet, and I suspect this one also causes a lot of slow down.

I'm going to investigate the design of the database. I've never studied MySQL thoroughly since my main interest in web development is the front end side (Javascript, Css, etc). However I need to catch up on optimization techniques because the stories table is nearly one gigabyte and it keeps growing. Something is not quite right with the way I've designed the table, or the indexes.

Just how effective is the Shared Stories cache?21 September 2015
Today I implemented a simple log for the cache and a corresponding report in the "administration" panel for the website. As you can see the Study page caching, which was meant to improve the page loading time, hasn't been very effective so far:

That's because the cache only lasted an hour, and with visits spread across thousands of kanji pages, the cache typically wouldn't last long enough for another visitor to benefit from it.

I've now set the cache of the shared stories list to 12 hours, and the effectiveness is closer to 30% as of writing. Now I have real numbers, and hopefully we will see at least every second request to the Study page to benefit from the cache.

Small fixes following yesterday's update18 September 2015
The timezone setting for the server was set incorrectly, so that due cards and "reviewed today" count would not update at the usual time. This is now fixed. Remember to restore your timezone setting in the Account page if you tweaked it yesterday. Thanks for faneca and Daniel for the report!

Update : three minor fixes:

  • Fixed broken /sightreading URL
  • Fixed broken article link in Manage page to the RTK Supplement news update
  • Fixed error when clearing the learned kanji list ("Clear" in Study sidebar)
I haven't got any other emails since the update so it looks like the update went smoothly!

Today's update : Optimizing the Study page17 September 2015
The website has been updated today with changes that should improve the loading times of the Study pages.

The Shared Stories list on the study pages is now cached. I have set the "lifetime" of cached stories initially as low as one hour. So eg. if you share a new story, or upvote someone else's story, it may take up to an hour to be reflected in the page. Update: it may take several hours, up to a day to notice a difference because the cache is very conservative atm (probably too much) .

This is obviously a usability problem. How do you signal to users that the content is not immediately updated, but will be eventually? It's not ideal, but I think the tradeoff is worth it. It's not critical for votes, reports, and shared stories to be reflected in real time on the website, and this saves a lot of unnecessary queries on the database.

I will keep an eye on just how many pages are cached, based on the user activity, and then increase gradually the effect of the cache until it provides a significant speed improvement. In theory, updating the Shared Stories list even just once a day should provide more significant gains. But I wanted to think about how that is going to work usability wise so I will finetune it over time.

Since the website has been entirely upgraded to a more complete framework, there may be a few bugs that slipped through my tests. These should be very easy to fix. If you find an issue please let me know and I will fix it asap.

...more in the news archive.