noun
dead center of a bat; sweet spot
Baseball term for the optimal hitting area on a bat. Also written 真芯.
See also: 真芯
ボールを真っ芯でとらえた瞬間、手応えを感じた。
The moment I caught the ball on the sweet spot, I felt the solid contact.
彼はバットの真っ芯に当ててホームランを打った。
He hit a home run by connecting with the dead center of the bat.
Same meaning, but 真っ芯 is a more emphatic or colloquial variant with the prefix 真っ.
Formed from prefix 真っ (ma', intensifier) + 芯 (shin, 'core'). The geminated form 真っ芯 is a colloquial emphatic variant of 真芯.