first tea ceremony of the New Year
Refers specifically to the first tea ceremony gathering held in the new year, often in January, marking the start of the tea practice year.
今年の初釜は一月五日に行われます。
This year's first tea ceremony will be held on January 5th.
初釜に招かれて
I was invited to the first tea ceremony of the year and went dressed in a kimono.
Compound of 初 (hatsu, 'first') and 釜 (kama, 'kettle'), referring to the first use of the tea kettle in the new year.