Upgi Janggi (업기장기) is a two-player variant of Janggi featuring a stacking system.
Players may stack their Chariots, Cannons, Horses, Elephants, and Soldiers into a single combined piece. However, only two pieces may be combined at a time.
A stacked piece may move in one of two ways:
It may move while remaining stacked, using the movement ability of either component piece.
Alternatively, the stack may be partially separated, allowing one of the pieces to move independently according to its normal movement.
The Janggi rule prohibiting Cannons from jumping over or capturing other Cannons remains in effect, regardless of whether the moving Cannon, the screened Cannon, or the target Cannon is stacked with another piece.
This also applies when a stacked piece containing a Cannon moves as a stack using the movement rules of the non-Cannon component.
However, if the stack is separated and only the non-Cannon piece moves, it may capture normally according to its own movement rules.