Meaning: HONE, SHARPEN
Etymology: The left radical means stone. The character to the right represents two forked sized sticks of uniform size. Thus, the association is to make stones uniform in size, weight, etc.
If you've seen a Japanese castle wall, you'll realise why this is important.
Mnemonic: HONE STONE WITH TWO FORKED STICKS.
(Based upon Henshall, 1998)