Is the challenger supposed to [wipe the goban]?
As well as being the challenger in that match, Shibano is also almost twenty years younger than the challengee, Cho U. In fact, Shibano was only nineteen when he took the title.
Perhaps that played a role?
I don’t think so. I believe it’s just an etiquette thing. Just like Alexander said.
That reminds me that I don’t have a blanket yet!
I have a hooded velvet cloak. I think I will use it as my “battle garment” from now on.
The fan (hot) is a bit contradictory with a blanket (cold).
Maybe it’s a “modest” custom of sorts?
Hoshiai Shiho 3p, today’s challenger for Female Honinbo.
I must introduce this habit to my local go club.
I am pretty sure our boards haven’t been wiped since longtime! 
Convincing people to wash stones could be more difficult. Even in this period of Covid curse, we don’t clean stones. Someone uses gel to clean their hands but that’s all.
In live tournaments we are more accurate and we use gel before and after game. We should do that also in club.
It isn’t strictly related to this topic, but I love fidgeting and recently I made some begleri (Greek people should know what I’m talking about). Last week I actually played go at the club while fidgeting with one of them.
This triggered a memory a long long time ago when I was just a little kid in the classroom where my teacher would always play with the 手轉球 (“exercise balls” if want to call it that, and his was made of wood), and sometimes he would play it during a game.
And Fujisawa Rina kept her title this year.
I have these.
They are made of enamelled metal and they have a ringing sound.
I think they would be quite annoying while playing. 
In Italy we call them just Chinese balls.
I was looking on amazon few days ago and I found out that there are similar objects named Baoding balls. Also Wikipedia has a page about them.
I think it’s a funny name since “ding” is very appropriate for their sound.
I always saw them smooth while in your picture they aren’t.
I had a set of those as well for years, I gifted them.
I’ve seen metal ones and wooden ones, and wooden ones can have various shapes with carvings and silent. The name came from a place in China, and the sound is a happy coincidence I think.
I’d really love to have some with a pretty wooden texture.
I could buy them online but I don’t trust pictures on amazon and other similar sites.
Other shapes are very nice too.
A few years ago fidget spinners were very popular.
As long as they are not noisy and put ostensibly in front of me i can stand that.
I loaned one spinner from my daughter and used it at the office, before Covid
On second thought why would we need spinners, Chinese balls, etc., when we have go stones in a bowl?
I do fidget a lot with the one stone I have in my hand while playing
@Atorrante - this is why not 
and @Lys - you ain’t supposed to do that either
From Go etiquette at Sensei's Library :
