On top of the piston’s I’m guessing? That can be confusing because some manufacturers pistons have them, some don’t. Best thing to do is the match up the the relief’s for the valves on top of the piston, with the valves on the heads. You’ll notice the exhaust valves and the intake valves, ones larger than the other, so on top of the pistons, the valve relief is machined or casted with one side slightly larger than the other for clearance