inkstone well; inkstone reservoir
The depression in an inkstone (硯) that holds water or liquid ink during grinding.
I drip a little water into the inkstone well.
A container for holding liquid ink, typically used with a brush. Less common than 墨壺 (すみつぼ) or インク壺 in modern contexts.
As part of calligraphy tools, I dip the brush into the inkpot.