Single Comment

The question that would then arise about dropped pieces is 'what about
promoted Pawns?'  Would the player be allowed these new pieces if
captured?  Or would the promoted pieces by reduced to Pawns and
discarded(since the Sho can spawn them anytime).

If the promoted pieces were allowed to be played by the captor, this could
make for a potentially crowded field(though unlikely no more so than the
standard game).  If not, the promoted piece could be sacrificed, knowing
that the captor would not be able to take advantage of the capture.

I would opt for not allowing the player to drop promoted pieces.

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Another idea: Restricting promotion to capture pieces. A player would only
be allowed to promote to a piece which had been previously captured by the
opponent. This would mean that unless the proper piece was available, the
player would not promote when entering the seventh and eighth rank. But on
the ninth rank, the Pawn could freely promote to the Kozune since it is not
part of the initial setup.