I've been wondering what would be the strongest piece in the game. You would expect it to be the Marshall but that's not completely true in my opinion. I think Generals are more powerful in the game.
The reason for this is because these strong pieces are meant to use in an offensive way, walking on your opponent's side of the board to take anything that moves. Once you know where your opponent has his Marshall, all you would have to do is avoid that piece and take anything else that moves. Well, until you hit your opponent's General, after which the Colonel becomes the most powerful.
Why isn't the Marshall more powerful? Simple. When walking around, you will need to avoid your opponent's spy, or lose it. And this spy is a defensive piece, lying in wait until it can capture your Marshall. And your opponent might just lure you to his spy.
So once you know where your opponent has his Marshall, you might consider taking his General with yours, after which your General will be able to take anything that moves, as long as it stays away from that opposing Marshall.
Also, when you manage to capture your opponent's Marshall with your spy, don't even hesitate capturing your opponent's General with your Marshall, because it gives you an undefeatable piece called General.
Well, as long as you avoid the bombs. :-)