Four chess squares plus four-and-a-half shogi rectangles by eight chess squares on the chess side by nine shogi rectangles on the shogi side. The length of the sides of each chess square is 1.25 the width of the shogi rectangles. The half shogi rectangles meet the chess squares and have the same dimensions as regular rectangles on the shogi side but may be 'half-square passant' every other move; if a tokin/pawn or keima/knight passes over them. By the end of the game, if on one side the number of times hsp is used is equal to the number of times hsp isn't used, it wins the bout if on the other side those values are imbalanced (which means victory may be determined by the time all tokin/pawns have been promoted). En passante (chess), castling (chess) and for both side retainment of captured pieces with the ability to place them back into bout for a ply are there, with pieces treating any square or rectangle of which any part of space of one touches any part of space of another as directly orthogonal to it.

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On Go proverbs:
"A fine Gotation is a diamond in the hand of a dan of wit and a pebble in the hand of a kyu" —Joseph Raux misquoted.

There is already a board game called Masterpiece. It's branded as the Art Auction game. It's actually quite fun, I'd recommend it.

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North Lecale

I must admit that I did not understand anything of the original post.

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A good system naturally covers all corner cases without further effort.