(2) The Pincers Cannons
In Chinese xiangqi books, it is referred to as “Cannon Smothered Mate” (闷宫). I prefer to reserve the term “Smothered Mate” for mating positions in which the Intercepting Forces comprise of enemy pieces only.
The red Cannon in the central file pins down the black Elephant and Adviser. Thus, when the other Cannon checks at the baseline, black is unable to lift the check with the Elephant.
This pattern of checkmate or the threat of it, appears frequently in real games.
The central Cannon, together with the opposing Elephant and Adviser, forms the IF, as in v1.
Red could have won with the Stacking Cannons checkmate, had both the black Advisers been on the 4th file, i.e. one in front and one behind the King. Is this a lost position for red then? No, red has a winning move.
The red King dominates the central file, releasing its intercepting power on the opposing King . Therefore, on C2=6, black is checkmated since he is unable to get the King out of check by playing K4=5 or A4-5.
AF: rear Cannon, assisted by the opposing Adviser
I F: front Cannon and the King