If you, or a loved one, are celebrating Japanese New Year, Oshōgatsu (お正月), you may need to do some shopping. During the December in 2021, we got snowed in really bad, and my wife couldn’t go to the local Japanese supermarket to buy goods and ingredients herself. So, I went on her behalf using public transportation to downtown, got the goods, and came back.
To save other husbands (or anyone else who likes to celebrate) some uncertainty, here’s a recommended list of things to get and why. I purposely took photos of my own at the local Asian grocery store, rather than stock photos, because I felt this would help readers on the ground more, especially if they can’t read Japanese.
New Year Altar
A common tradition in Japan is to get a kagami-mochi, kind of like so:

Kagami-mochi are a pair of mochi (rice cakes) stacked one on top of the other, usually with a ribbon around it, and a bitter orange or other decoration on top. I’ve talked more about it here. These are often available at any Japanese grocery store, and include instructions on how to set it up. Remember, on January 11th, there’s a separate ceremony to break open the mochi and cook it for good luck.
Soup Ingredients
There are several items, often available in your local Asian food store, that are essentials for Japanese cooking during New Years.

First, is naruto, shown on the left:


This is not to be confused with the manga series. Naruto is a food that usually comes in a long roll and is sliced thin and added as a topping to soups and ramen during New Years. A similar food, shown on the right, is kamaboko. Kamaboko often comes frozen, and has to be thawed out first, then sliced and added to soup, including toshi-koshi soba which is eaten the night before New Years.
Another food often used, especially in ozoni soup (eaten on New Year’s morning) are mochi rice cakes:

There are many kinds, and cuts, so just find something that’s suitable for your needs. Out of the package, they are hard little bricks but when added to warm soup or baked in a toaster oven, they have a taffy-like consistency. Keep in mind that it’s possible to choke on mochi if you don’t chew thoroughly. They’re delicious but consider yourself warned.
Osechi
During New Year’s day, it is considered auspicious to eat certain foods on the first day. These are collectively known as osechi-ryōri, or just osechi. There are many possible foods to use in osechi, but one common one is kuro-mamé:
These are just sweetened black beans, and something I enjoy eating in particular. In the same picture, shown below are yellow kuri-kinton which is a kind of walnut paste.

Another great choice are lotus root, or renkon. They look like huge tubers at the store…

But when peeled, sliced thin and cooked in broth they look more like this:

They have a nice consistency like potato and are delicious to eat. Highly recommend.
Finally there are special chopsticks you should pick up for osechi:

The chopsticks themselves are nothing special, but using bright, clean chopsticks with auspicious decorations on them, I believe that this helps symbolizes a fresh (and positive) start for the new year.
Conclusion
This not an exhaustive list of goods for Japanese New Year, but I hope this helps cover basic foods and goods you might need to enjoy New Year. Your mileage may vary. I will also try to update and polish this up as time goes on.
Good luck!