This page explains how Jonathan Chu (USATT# 57948)'s rating went from 1940 to 1949 at the 2009 Spinathon held on - 24 May 2009. 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.