score:11
During the new year holiday season in Japan (Jan 1 to Jan 3 for 2020) most shops and restaurants close. The smaller the establishment, the more likely it is to be closed. December 31 is usually a working day, but shops might close earlier.
Japan doesn't completely stop though during the holidays. Chain restaurants, supermarkets, large department stores, and commerce in large tourist areas like Shibuya, Shunkjuku and Akihabara are likely to be open for business.
Tsukiji in particular is mostly in the middle of an office area, and has mostly small family owned shops that are very likely to be closed for the holidays. Some chain sushi restaurants like Sushi-zanmai or Sushiko might be open.
If you're interested in visiting a specific shop, I suggest you look at their website, or call them to ask for their new year holiday schedule.
Upvote:6
I have not been out and about on holiday period, but I would assume most shops in Japan are outright closed on those days, Tsukiji or not. Most of the locals are out on holiday to spend time with family or such which means storefronts are usually closed as well. This would mean that finding a similar experience during those dates might be difficult.
For the shops considered part of the market, I would recommend checking under the ご飲食 section in the Tsukiji webpage. Some shop pages have phone numbers, so you may be able to call ahead for any shops you might be interested in visiting to see if they will be open on that day. The webpage/phone app Tabelog is also useful for finding contact information.