noun, noun which may take the genitive case particle 'no'
first time this year
Used to describe something happening or being done for the first time in the current calendar year. Often appears with the particle の to modify a noun.
The first snow of the year fell.
Today is my first day at the office this year.
Compound of 今年 (this year) and 初 (first). The reading ことしはつ follows standard rendaku rules for 初.