While it is true that ya = ma' = a', and ga = pa', there was no such thing for ca' or da'. If Advancer capture would be worth having its own symbol, it would seem more natural to me to make that c'. I am not sure it is, however; Advancers are not that common, so that it isn't too bad if their description is a bit complex. Furthermore, I can imagine several variations on this kind of capture, e.g. where the piece ends two steps before the piece it captures, or that it captures the nearest piece in the direction it moves. Having a dedicated notation for each of those would lead to a proliferation of dedicated (rarely used) modifiers. I'd rather have a powerful general system relying on commonly used modifiers.
Advancer capture seems related to Fire-Demon burning. It would be nice to have a method for appending a 'burning leg' to a move, which would not actually be made by the moving piece, but would execute the operation specified by the mode (c, d or e) there whenever it is possible, but would not block the move if it is not possible. Say we would specify this as t (for 'terminate'). Then the Advancer could be yaftcQ: a Q move to an empty square with range toggle (y), after which the move can terminate, but must continue in the forward direction (with a single step because of the range toggle) to capture if there is anything to capture. Without the f it would have been a Queen that burns like a Fire Demon. (A Fire Demon would be vsvmca'tcQaamcatcKamcatcK.)
[Edit] An alternative for using a new modifier is to indicate burning by cc (or dd). Duplication of characters is a common device even in the original Betza notation (e.g. NN = Nightrider, ffN = Shogi Knight). An Advancer would then be yafccQ. There would be no need to invoke quoting, or use the t. The latter could be used as an alternative to a, for starting a new leg with toggled range (so that it would obviously stand for 'toggle'). That would allow range toggling on a capture, such as would be needed to describe Fire-Demon-like burning (mctccQ = slide to move or capture, and then burn all adjacent foes).
While it is true that ya = ma' = a', and ga = pa', there was no such thing for ca' or da'. If Advancer capture would be worth having its own symbol, it would seem more natural to me to make that c'. I am not sure it is, however; Advancers are not that common, so that it isn't too bad if their description is a bit complex. Furthermore, I can imagine several variations on this kind of capture, e.g. where the piece ends two steps before the piece it captures, or that it captures the nearest piece in the direction it moves. Having a dedicated notation for each of those would lead to a proliferation of dedicated (rarely used) modifiers. I'd rather have a powerful general system relying on commonly used modifiers.
Advancer capture seems related to Fire-Demon burning. It would be nice to have a method for appending a 'burning leg' to a move, which would not actually be made by the moving piece, but would execute the operation specified by the mode (c, d or e) there whenever it is possible, but would not block the move if it is not possible. Say we would specify this as t (for 'terminate'). Then the Advancer could be yaftcQ: a Q move to an empty square with range toggle (y), after which the move can terminate, but must continue in the forward direction (with a single step because of the range toggle) to capture if there is anything to capture. Without the f it would have been a Queen that burns like a Fire Demon. (A Fire Demon would be vsvmca'tcQaamcatcKamcatcK.)
[Edit] An alternative for using a new modifier is to indicate burning by cc (or dd). Duplication of characters is a common device even in the original Betza notation (e.g. NN = Nightrider, ffN = Shogi Knight). An Advancer would then be yafccQ. There would be no need to invoke quoting, or use the t. The latter could be used as an alternative to a, for starting a new leg with toggled range (so that it would obviously stand for 'toggle'). That would allow range toggling on a capture, such as would be needed to describe Fire-Demon-like burning (mctccQ = slide to move or capture, and then burn all adjacent foes).