Once in a lifetime encounter in Kanji

It is a once-in-a-lifetime encounter, meaning it will never happen again.
“一期” means “lifetime” and “一会” means “one time encounter”.
One of the terms describing the spirituality of the tea ceremony. I thought that today’s meeting would be a once-in-a-lifetime meeting, and I taught them that it is essential to interact with both the host and the guest with kindness and sincerity.
In turn, a once-in-a-lifetime encounter. To be a once-in-a-lifetime experience. once‐in‐a‐lifetime chance. Treasure every meeting.

Japanese says Ichi-go-ichi-e.