This page explains how Lanfei Chen (USATT# 197032)'s rating went from 1666 to 1789 at the Westchester 2021 October Open held on 30 Oct 2021 - 31 Oct 2021. 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.