What holiday is the year mentioned in Su Dongpo's poem "Keeping the New Year's Eve"?

"Keeping the New Year's Eve" by Su Dongpo The New Year mentioned in the poem refers to a traditional Chinese festival: the Spring Festival.

On New Year's Eve, it is customary to put up couplets and observe the New Year's Eve.

Watching the New Year

Song Dynasty: Su Shi

If I want to know the end of the year, it is like a snake going to the gully.

The scales are half gone, and who can cover them up?

What if I want to tie my tail, even though I am hardworking, I don't know what to do.

The children are strong and do not sleep, and they are happy to watch each other at night.

Don't sing to the rooster in the morning.

Sitting for a long time, the lamps fall, and I rise to look at the Big Dipper.

If there is no year next year, I am afraid of wasting my time.

It's a good idea to work hard tonight, but I can still boast about my youth.

Translation

We must realize that the year we are about to say goodbye to is like a long snake that swims towards a valley.

Half of its long scales are gone, and no one can stop it from leaving!

What's more, I want to tie up its tail end, though I know diligently that there is nothing I can do about it.

Children don't sleep and struggle hard, and they stay together in the night, laughing and clamoring.

The morning rooster, please don't crow, and the sound of the drums is frightening.

Long night sitting on the lamps falling down, get up to see the Big Dipper has been oblique.

Will there be no annual festival next year? I'm afraid that my heart will be out of whack again.

This is one of the best nights to be a teenager, and I'm sure you'll be able to boast about it.