noun
cutting the New Year's rice cake; kagami-biraki (Jan 11)
A traditional Japanese ceremony held on January 11th (or sometimes later) where a large round rice cake (鏡餅) offered at New Year's is broken or cut into pieces and eaten, often in a sweet red bean soup.
鏡開きで割ったお餅をぜんざいに入れて食べました。
We put the rice cake broken at the kagami-biraki into sweet red bean soup and ate it.
noun
A celebratory custom at weddings, company parties, or other festive events where the wooden lid of a sake barrel is struck open with a mallet and the sake is served to guests.
結婚式の披露宴で鏡開きが行われ、樽酒が振る舞われた。
At the wedding reception, a kagami-biraki was performed and sake from the barrel was served.