This page explains how Brian Sun (USATT# 91741)'s rating went from 1925 to 1856 at the US Open held on 17 Dec 2017 - 22 Dec 2017. 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.