Savings
You keep all of your shellfish under a roof down the street and it's your savings. Shellfish used to be used as money way back, and these aren't shellfish you're spending, they're ones you're saving up for later.
Imagine walking down the street to deposit more shellfish into your special savings and gaze happily at the huge pile you keep far enough away that you aren't tempted to spend it.
ちょ
たくわ
None
When you want to withdraw from your savings you force yourself to use chopsticks (ちょ) to pick up the shellfish. They're especially slippery, hard to use chopsticks too, that way it's really hard to take too much out of your savings.
Imagine trying to lift up a shellfish with a pair of smooth chopsticks. It slips right out. Ugh! I guess that's good though, because it's a savings for a reason (you shouldn't be spending it)!