My Lands: Black Gem Hunting

cost 10 BG.

or better option closed gate cut spam attack automatically

While I agree that spamming is a poorly designed part of the game that needs to a fix, I think it needs a better fix than 10bg toll or clearing spams via fast closing gate...

I think a simpler solution would be to limit the range players can attack from, which would fall in line with something like Market Range science.

For example, the Missions Control science could be modified to additionally add that each level researched yields +2 attack range for the player. At max this would be ~18 or something. This range of kingdoms is somewhere between 5-9 hours of attack distance, meaning no player could attack at durations greater than these lengths.

I think this would be a good solution because it doesn't change how many players are affected while also addressing a large part of the spamming (duration).
I don't think any player makes actual attacks longer than 10 hours anyways so nothing is missed by limiting the attack launch range to a more reasonable amount to mitigate spam lengths.

I AGREE