Jiugong grid: find the rules and fill in the appropriate numbers 9, 11, 10, 16, (), 12, 17, 8 and 5 in the blank number

Jiugong grid: find the rules and fill in the appropriate numbers 9, 11, 10, 16, (), 12, 17, 8 and 5 in the blank number

9  11  10
16  2  12
17  8  5
Fill in 2 in brackets