NPO Energomash
As stated in the History section, the RD-120 was used as the first practical application of the oxidizer rich staged combustion with kerosene propellant at NPO Energomash, before tackling the RD-170. So, while this later family of engines have more aggressive performance parameters and the original project (the RD-123) predates the RD-120, it was indeed the first actual design of the series development.