This page explains how Hsu-Chang Lu (USATT# 84845)'s rating went from 1871 to 1815 at the LYTTC Friday Pro League event from 20 Dec 2019. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.