# 3.5. What does 1/5 or 1/10 mean? (Go)

## Description

This article is from the Go FAQ, by
Morten PAHLE gofaq@pahle.org.uk with numerous contributions by
others.

# 3.5. What does 1/5 or 1/10 mean? (Go)

This 'abbreviation' used on Go servers indicates the time limits of

proposed matches.

Often, rather than having a time limit for each move or a time limit

for the whole match, many Go matches have two time limits. One is the

'basic' period and the other is the 'overtime', or the 'byo-yomi'

periods.

The first part of the 'abbreviation' refers to the basic time limit.

Often on Go servers, the basic time is one minute. You can play as

many or as few stones in this period as you like. As soon as the basic

time ends the first byo-yomi period starts.

The second part of the 'abbreviation' refers to the length of the

'byo-yomi' periods.

Byo-yomi periods require you to maintain a certain average pace: you

must play a certain number of stones (typically 25) within the time

period.

If you play the 25 stones within the byo-yomi period, you get another

byo-yomi period. So if the byo-yomi period is 10 minutes, as soon as

you play stone 25, the clock starts again at 10 minutes. (Even if you

have used less than 10 minutes to play your 25 stones).

If you do not play 25 stones during a byo-yomi period, you lose the

match.

So, if someone proposes a '1/10' match, that is a match with a main

period of 1 minute followed by repeating byo-yomi periods of 10

minutes each. So, when the match starts, the clock counts down from

one minute, then resets to 10 minutes and starts counting down again

(and again).

In this fashion a 1/5 game with 200 moves cannot take more than 42

minutes: first, each player gets 1 minute, then each player gets 5

minutes to play 25 stones, another 5 minutes for the next 25, etc. If

each player took the maximum time, each player would get one minute

plus 20 minutes (in four 5-minute byo-yomi periods) to play all their

100 stones, for a maximum match time of 42 minutes.

This and other terms used on the go servers are listed and explained

in <http://home.snafu.de/jasiek/slang.html>

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