止（と·める、と·まる、シ）

Meaning: to stop

My hack: I can’t claim credit for this one. (I learned this from a book called Kanji Pict-O-Graphix, which has about 1000 mnemonics if you’re interested in seeing some other memorization ideas.)

The first stroke (the longer vertical line) is a police officer, and the little horizontal stroke is his arm out to signal traffic to stop. The third stroke is a child waiting to cross the street, and the final stroke is the ground.

This character is on the cover of the book:

Kanji Pict-O-Graphix

Note: Just in case anyone is suspicious, I have no affiliation with the author of this book and I am not being paid to plug it. I’m just putting it out there as an option for anyone who is interested. For more details on this book and others, check out my reviews.