Readings & Meanings:
In this way, tofu is a product of hardening soymilk.
This is the reason he quit his job.
If you want to talk about karma, try "spitting at heaven."
When a box surrounds another kanji, it's not considered the くち radical any more. Instead, it's くにがまえ, an enclosure or surrounding.
Inside the box is a character that looks like 大. One would think that this means "big enclosure," but Kanji Networks says differently:
But that doesn't really help with a mnemonic.
...shows bedding on which rests a person or object → depend; cause; be connected with (← superimposition) → be based on; be due to; therefore; consequently.
Think of something big, springing from a little box. Think Pandora. All the big troubles of the world came from inside that box. The box is the cause of something greater.
Spitting at Heaven?
因果応報 is more of a concept than a word. 因(cause) + 果(effect) + 応報(retribution) = karma, just deserts, comeuppance.
So what's "天ツバ"?
天 is heaven. ツバ is 唾, or spit.
It's a phrase that is shortened from "天に唾する", which is shortened from "天を仰ぎて唾す". There are a few versions, but that one is the classic. Note the す at the end, an old way of saying する.
What do you get when you spit (upward) at heaven? Instant karma, all over your face.
One more thing about spit: 眉唾.
In olden times, there was a Japanese superstition that, if you heard something suspicious, you should rub spit on your eyebrow, and it would have a knock-on-wood effect. Lick the tip of your finger and slide it across your eyebrow from the center part to the side of your face.
眉 is eyebrow, 唾 is spit.
Today, 毎唾 is a word indicating suspiciousness. When you doubt the story someone is telling, you can say: