Xu Collection, Upper Volume
Radical: Gate (mén)
Zha
Kangxi strokes: 13
Page 1333, Entry 01
Pronounced ya.
According to the Explaining Graphs and Analyzing Characters (Shuowen Jiezi), it refers to opening and closing a door.
According to the Expanded Rhymes (Guangyun) and the Collected Rhymes (Jiyun), pronounced he. It refers to closing a door.
According to the Correct Meaning Through Investigations (Zhengzitong) and the Collection of Characters (Zihui), this is a variant form of the character zha (sluice).
Note: Currently, when grain-transport vessels travel back and forth, stones are inserted on the left and right like a gate, and wooden boards are installed to hold back the water. It is opened and closed at appropriate times to allow boats to pass. A water gate accommodates one boat, and they pass through in succession. The gate is called a sluice gate (zha men), and the river is called a sluice river (zha he). Officials are appointed to manage the sluices. The Explaining Graphs and Analyzing Characters states it refers to opening and closing a door, but the details are unclear. The Collection of Characters broadly states it is a variant of zha (sluice), which is incorrect.