This page explains how Emiko Hosoya (USATT# 223357)'s rating went from 1289 to 1288 at the 2023 Arizona Open & Giant Round Robin held on 23 Sep 2023 - 24 Sep 2023. 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.