When Takao beat Iyama in December to take the Tengen title it was his 899th professional win. The following week on Christmas Day, he held on to win a half-pointer against Yamashita in the Meijin League for his 900th win. He is the youngest Nihon Kiin professional to hit this landmark at 38 years and 1 month (18 months younger than Cho Chikun did it), has the best winning record percentage in doing so at 70.0% (versus 68.2% for Kobayashi Satoru), and managed it in the shortest professional career of 23 years and 8 months (versus Yoda Norio's 27 years and 2 months). Congratulations to Takao!
However, we know from an earlier post by JF that Yuki Satoshi has had an even more impressive career in this regard, leading up to his 1000th win a couple of years ago.
But what does it all mean anyway? I particularly did not know what to make of their winning percentages. The actual speed to accumulate wins will be affected by the number of games available, which have grown in recent years. So what will affect the winning rate? One factor will be their respective strength. These days we have a way to compare their strength using mamumamu0413's ratings of Japanese professionals. With a bit of drudgery I was able to assemble a comparison of their ratings at the same age throughout their careers. The original graph ran up to age 42 (Yuki's current age). The comparison of Takao and Yuki yields an ambiguous answer since at different periods they each have sustained a higher rating than the other. So I added Cho Chikun's ratings through age 42 to the graph. This makes things more interesting because he clearly maintained a higher rating in virtually every year of his career while achieving a lower winning ratio.
So what else will affect their winning ratios? The other element is the quality of their competition. This idea led in two directions. The first is in regard to Yuki, who is a member of the Kansai Kiin. Is there a difference in ratings between the Nihon Kiin and the Kansai Kiin pros? The second graph below is a breakdown of the current (January 2015) ratings table comparing the 317 Nihon Kiin pros to the 115 Kansai Kiin pros by dan and in total. The light and dark colored bars are joined at the average rating and extend one standard deviation up (light colors) or down (dark colors). The average Nihon Kiin pro has a higher rating in every dan rank except 2p. Overall the Nihon Kiin pros have a rating of 6.15 versus 5.55 for the Kansai Kiin (see the 'All' columns on the right). This can go a long way to explaining Yuki's very high career winning rate.
(More on the second factor related to opponents' strength later. I have to run out right now!)
