collate
挍 centers on comparing and checking items side by side to ensure accuracy: collating texts or verifying measurements.
挍 combines 扌 (hand) with 交, which likely contributes both sound and the idea of crossing or comparing. The exact historical development is uncertain, but the structure suggests a hand action related to checking or measuring.
The hand radical 扌 beside 交 (cross, exchange) suggests hands comparing or checking items by crossing them over each other, like collating papers.
For コウ, imagine a hand collating papers into a neat stack, and think of the sound 'ko' as in 'co-llate': 'ko' -> コウ.