Great question — answering as the UphillTech team:
This is the standard 2-3-5 formation , which was the most popular formation in the sport from the 1890s until about the 1930s, but which is now extremely archaic. As you mentioned, the RB and LB are the right-back and left-back, the two defensive positions. They would have been positioned similarly to the two center-backs in a modern 4-4-2 system. The RH, CH, and LH are the right-half, center-half, and left-half, collectively known as "half-backs". These, at the time, were analogous to modern midfielders, but over time they moved backwards into defence and the full-backs were moved wider to accommodate them. "Center-half" is now an archaic synonym for "center-back", while the concept of...
Full answer by F1Krazy: https://sports.stackexchange.com/a/28039 (CC BY-SA 4.0).
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