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(sound of) hitting repeatedly; pummelling; clashing; clacking; clicking (e.g. of go stones)
「丁丁」 has another reading with different meanings.
打々と音が響き渡っていた。
The sound of clacking echoed.
石が打々とぶつかっていました。
Stones were clashing repeatedly.
打々と太鼓を叩いていた。
I was drumming repeatedly.