This Terrace rule variant expands offense by allowing a piece to capture diagonally either up or down if its top is at least as high as the top of the piece it is capturing. This means that a piece that is one size smaller but one level higher can make the capture, and pieces can capture diagonally upward if they are one size larger than their target or larger. The new rule makes it easier to break up defensive formations. It adds a lot of tactics to the game. [I am not the originator of this variant; in fact, I cannot recall where I first learned it.]
"Rank Capture beautifully blends-in more chess-like complexity to the game without losing the hallmark simplicity of Terrace. The added challenge is exciting, especially for seasoned players.
The only change has been to the capturing rule. All other rules (for moving pieces, etc.) and set-ups remain the same. Remember two things...First, Rank corresponds to the size of the piece. The "a" pieces, including the "t", are the smallest and lowest rank, while "d" pieces are the largest and highest rank. Second, the piece which holds the "high ground" has the advantage.
Attacking down to the next level (diagonally only)...the capturing piece can be one rank smaller than the piece it is capturing.
Attacking up to the next level (straight only)...the capturing piece must be at least one rank larger than the piece it is capturing.
Attacking on the same level (to an adjacent square only)...the capturing piece must be at least the same size of the piece it is capturing.
Assassination...here's a "twist" to this game which makes it especially fun...a piece with the rank of one (including the "T") can attack a rank "d" piece which is straight above it on the next higher level.
Tom also points out that (except for assassination) if a piece is in the correct location to attack another piece, a quick way to determine if it has the rank to make the capture is to look and see if the top of the capturing piece is at the same elevation or higher than the top of the piece to be captured. This "visual" tip-off is a quick and easy way to assess the situation.