Timing marks on chain driven Mazda 6 2.3 2003?

On a chain-driven engine, as used in the Mazda 6 2.3 2003, the timing is controlled by the position of the crankshaft and camshaft sprockets. The sprockets are aligned using dowel pins, and do not require timing marks. The position of the sprockets is determined by the number of links between the sprockets, and the pitch of the chain.