British Go Journal No. 20.  July 1973. Page 9.
When one plays Go, in Britain or abroad, one should follow the normal standard of etiquette in playing. This standard is, of course, Japanese. This need not be rigidly followed, but it is only polite, especially when playing Japanese, to observe these rules.
First, there is the custom of bowing before the game. This is usually coupled with the word 'onegaishimasu' (o-ne-gai-shi-mas) which means 'if you please'. This is not always done by the Japanese but should be followed in major and tournament games.
Second, to take a move back without asking your opponent's permission is not only rude to your opponent but allows you to check a situation without having read it out in your head. Don't be so lazy!
Third you should always thank your opponent after the game. This seems such a small point that you may wonder why I mention it at all. It is important because it can leave bad taste if your opponent hardly bothers to admit your existence after the game.
Finally, always clear your own stones away, moving your opponent's to one side or to the other side of the board. This is normal in Japan but not so in England. It may seem impolite but it is to avoid both players puttng their hands in the same bowl.
All these are not important but it does have an exceedingly good impression on visitors from Japan and it sets a good example to beginners and players in your club.