i will be flying from Los Angeles to Japan with a stop in Beijing Capital Airport.

First, you can confirm with your airline company whether you can enjoy the Baggage Check-through Service. If yes, then you don’t need to claim your baggage. Otherwise, you may need to pick up them. You still need to go through the immigration procedures as the following.
Flight Arrival - Transfer Procedures - Border Inspection - Security Check - Custom Inspection - Waiting & Boarding