KanjiJLPT N2
Pair

pair, set, comparison, counter for pairs

Mnemonic

"Once more!" you shout, tugging on your left glove. "once more!" you cry, tugging on the right. Two identical actions, two identical gloves — now you hold a perfect pair, matched side by side like mirror images on your hands.
Additional thoughts
The kanji 双 literally stacks two 又 (once more) next to each other. Visualize the symmetry: left glove, right glove, each pulled on with the same repeated motion. Repetition of the same gesture naturally produces a matched duo.
Quick recall
Shout "once more" twice and you pull on a pair of matching gloves.

Details

The keyword for 双 is pair. This kanji refers to a set of two matching or complementary items, emphasizing the concept of things that naturally come together as a matched duo. It conveys the idea of two things of the same kind existing side by side, such as a pair of hands or a pair of objects. The character captures the essence of duality and symmetry inherent in matched sets.
On'yomi
そう
Kun'yomi
ふた、たぐい、ならぶ、ふたつ