Does the +1/+0 counter accumulate each turn if you attack with the same creature. I am thinking yes, as the text doesn't say "until end of turn". Is this correct?
You are incorrect on a couple of things here.
First of all Gruul War Chant, doesn't provide any sort of counter, as it doesn't use the word 'counter' anywhere on it. It simply provides a static buff to your creatures that are attacking.
Second, Gruul War Chant only cares if your creatures are attacking or not attacking. If they are attacking they get the buff, if they are not attacking, then they don't.
So declaring a creature as attacker more than once over several turns, or even during the same turn, doesn't do anything significant.
Now Gleam of Battle does indeed deal with counters. So when you attack with a creature, Gleam of Battle triggers and puts a +1/+1 counter on that creature. And unless something happens to the creature (it is bounced, flickered, killed or exiled) or to the counter, that counter will stay on the creature.
So when you next attack with that creature, Gleam of Battle will trigger again giving the creature another +1/+1 counter.
Does the +1/+0 counter accumulate each turn if you attack with the same creature. I am thinking yes, as the text doesn't say "until end of turn". Is this correct?
Thanks,
First of all Gruul War Chant, doesn't provide any sort of counter, as it doesn't use the word 'counter' anywhere on it. It simply provides a static buff to your creatures that are attacking.
Second, Gruul War Chant only cares if your creatures are attacking or not attacking. If they are attacking they get the buff, if they are not attacking, then they don't.
So declaring a creature as attacker more than once over several turns, or even during the same turn, doesn't do anything significant.
Hope that helps explain things for you.
So when you next attack with that creature, Gleam of Battle will trigger again giving the creature another +1/+1 counter.