I think perhaps you are thinking about 5's incorrectly. They are strong, but they must be used defensively more than offensively. 4's are better offensively as you mentioned. Any 4 can attack literally any non-bomb piece if it is backed up by a sapper. Why? if the enemy 5 recaptures it, the sapper is there to take it off the board. teams of sapper + 4 and spy + 5 work well together, as the spy identifies the potential sappers lying in wait.

Thad, if a mine would explode after anyone landed on it, then all you have to do is throw some poor 1's at them. The sapper gains value by being the only anti-mine piece. If you lose your sappers you must win every other piece and make the last move in order to win, so keep your sappers!

I would like to see a SuperEspionage version. Combine a spy + sapper, which each player has one of. Combine a spy + 5, which each players one of.

Throw away two of the one's in exchange.

Yes but if you have both 5's to your opponent's none, you no longer have to worry about an attack on your castle. Retreat your 5's to either side of it and whatever comes at it you can win by attacking first. Just remove all sappers in swaps ahead of time and the game is yours.

I think we need a "dark spy" piece. When it crosses the 5th rank, all of your opponent's spy data gets turned back to "?"

Maybe we need 2 boards, one game board as it is now, and one with our own labels. As the opponent moves on the game board, our labeled board gets updated automatically. So if I replace a ? with a 3 on my board, if the player moves the ? piece, on my board the 3 is moved to the same square.

If a 4 attacks a 5 and loses, shouldn't the 5 become revealed? Also if a 3 attacks a 4 and loses, the 4 should be revealed, shouldn't it? It can be "only one thing" so why not?

This then means, indirectly, Spies must be more valuable, since knowing what you are attacking can have a big payout.

I thought when pieces of same power attack each other both are removed. So if 5 strike 5, the striker wins in the way it is done on here? I thought ties were both removed.