What is a

Shiroboshi is a compound word: 白 (shiro) means "white" and 星 (hoshi - voiced tense) means "star." A "white star" in baseball is a "win." A 黒星 (kuroboshi) literally means "black star," and means a "loss."

This is relevant to the way wins and losses are written in print (triangles denote a tie). Wins are often denoted as white circles, losses as black circles, allowing one to graphically see patterns in wins/losses. Have a look at any of the teams' schedules for an idea of how easy it makes finding wins and losses on a page full of other information. Or here's a graphical look at the Pacific League so far this year:

Daiei      
Lotte      
Orix       R
Kintetsu   
Seibu      
Nippon Ham R

The "R" above would be a picture of an umbrella. And my cirles are octogons.

One of the Tokyo SABR members presented a presentation this past January where he looked at the wins/losses with the shiro/kuroboshi patterns in World Series and Nihon Series histories. He then calculated the likelyhood of a fourth game win based on the first three results. By representing wins and losses in this manner, it makes it very easy to follow. He asked me if they did this kind of thing in North America, but I'd never heard of it.

A glossary of Japanese terms is still on my TODO list. I want to do something like the Wikipedia for Pro Yakyu. That'll be my next big project, I think.