About the 15 d5 time control
With fifteen minutes and a five-second per-move buffer, this is the US Chess rapid benchmark. The delay means routine moves — king moves, checks, simple captures — cost nothing against your main time, keeping endgames fair without the clock-inflation of Fischer increment.
Compared to 15+10, the key difference is that time can never grow here: you cannot bank delay time the way you bank increment seconds. Good clock management matters as much as in pure rapid controls.
In short: 15 minutes per player with 5 second delay, in the rapid range. Tap below to start it now, or read more about how the time-control tiers compare.