Let’s say I play a game with Japanese ruleset where filling dames is not necessary. Is there any rule against it?
If I see a possibility of killing opponent group or whatever to gain points, but need time to read it out, I could use that to gain time in byo.
I usually fill dame even under Japanese rules, to avoid any confusion during scoring. I’ve never heard of any rule against it.
Of course there is no rule against it. Watch any Japanese pro tournament, they always fill dame. It’s interesting to watch because the players go from very slow as they use the Byoyomi to calculate all the values of small endgame, to very fast filling in dame.
That said, if there’s a lot of dame in my corr games, I’ll usually skip it. Ain’t nobody got time for that 
On the contrary, you technically have to fill the dame under Japanese rules (though the players may mutually agree to fill the dame after the end).
Of course if you play a dame to get more time to read if you can kill a group or whatever, then the opponent may answer that 0 point dame with a defensive move to avoid that problem, potentially costing them 1 point if it doesn’t actually work but worth avoiding the risk unless the game is very close.
Here comes some attitude again. Some players like to delay the forcing dame, will correct preventively their own defects (a sweet player, showing respect to the mental abilities of the opponent but i ll be afraid to lose a point at times) while others rush to force all the dame he can.
yep, but there is a chance my opponent does not detect my intention and not to add a defensive move.
Uhm. We haven’t played yet, have we? 
Also, I ≠ nobody 
Challenge sent!
There’s plenty of situations where your opponent might have a weakness in their territory, so they need to lose one point by playing inside their territory to fix the weakness… But only if you remove the outside liberties by playing the dame.
Sometimes the weaknesses are obvious, sometimes they’re not. If it’s not obvious, it’s up to the player to decide whether they want to play safe and add a move in their territory, or play greedy and don’t lose a point and hope their territory doesn’t blow up.
By not playing the dame, you’re allowing your opponent to not face the dilemma, and get extra points without risking their territory blowing up.
So, by all means, play the dame. They are part of the game. Then your opponent will either also play dame, or fix their weaknesses, or do something else, but that’s up to them.
Also, there are often reports of the autoscore being completely wrong when a situation isn’t entirely settled, and playing the dame somewhat reduces that risk.
Note that if you have conditional moves enabled, the dame phase can be sped up a lot.
Those forcing dames are also called teire, and for timesujis those work like every other sente, and also thats also the reason why you should usually fill the dames before scoring
If you’re smart about it and notice that some dames are teire against your opponent, you dont start the dame-filling by playing those moves but you play few gote dames first, then there is higher chance of opponent not responding correctly and blowing up when you do play them xD
I’d say that the only reason why you should leave dames on the board is when you’re playing online using japanese rules and you’re absolutely sure that none of the dames are teire. Or maybe with chinese rules if you’re absolutely sure that none of the dames are teire and there is even number of dames on the board.
Wheh playing on real bord and having to manually count the score, you should always fill the dames as that makes the counting lot easier regardless of the ruleset.