With this solving technique, we will prove the following assertions:
Each assertion is proved by a different chain of simple steps. The chains are static, which means that they do not rely on the conclusions of previous sub-chains.
The details of each chain are given below. Use the view selector below the grid to switch between the graphical illustrations of the different chains.
Chain 1: If H4 contains the value 1 then H3 cannot contain the value 1 (View 1):
(1) If H4 contains the value 1 then H3 cannot contain the value 1 (the value can occur only once in the col)
Chain 2: If H4 contains the value 4 then H3 cannot contain the value 1 (View 2):
(1) If H4 contains the value 4 then H6 cannot contain the value 4 (the value can occur only once in the box)
(2) If H6 does not contain the value 4 then D6 must contain the value 4 (only remaining position in the row)
(3) If D6 contains the value 4 then F5 cannot contain the value 4 (the value can occur only once in the box)
(4) If F5 does not contain the value 4 then F5 must contain the value 3 (only remaining potential value in the cell)
(5) If F5 contains the value 3 then E6 cannot contain the value 3 (the value can occur only once in the box)
(6) If E6 does not contain the value 3 then E1 must contain the value 3 (only remaining position in the column)
(7) If E1 contains the value 3 then E1 cannot contain the value 1 (the cell can contain only one value)
(8) If E1 does not contain the value 1 then I1 must contain the value 1 (only remaining position in the row)
(9) If I1 contains the value 1 then H3 cannot contain the value 1 (the value can occur only once in the box)
Chain 3: If H4 contains the value 7 then H3 cannot contain the value 1 (View 3):
(1) If H4 contains the value 7 then B4 cannot contain the value 7 (the value can occur only once in the row)
(2) If B4 does not contain the value 7 then B7 must contain the value 7 (only remaining position in the column)
(3) If B7 contains the value 7 then B7 cannot contain the value 1 (the cell can contain only one value)
(4) If B7 does not contain the value 1 then B3 must contain the value 1 (only remaining position in the column)
(5) If B3 contains the value 1 then H3 cannot contain the value 1 (the value can occur only once in the row)