This page explains how Keito Hosokawa (USATT# 217875)'s rating went from 1291 to 1289 at the South Bay Fall League event from 24 Sep 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.