Japanese people have common milestones of their lives, such as the year of 40, 60, 70 and so on. Just to let you know, they are called Fuwaku, Kan-reki, Koki respectively. Some people throw congratulatory parties when turning those ages. Today, I attended just such a kind of party, which is called Sanju, one's eightieth birthday.
About 20 years ago, I was doing the research work in graduate school to get my Ph.D., and my then boss was the professor of the biochemistry department. He retired at 65 and turned 80 and so his former students, including me, his colleagues, and the former staff members of his research laboratory got together to throw the party for him.
The following picture was shot just before the party. As you see, tables and chairs were set on tatami mats. It was a bit peculiar to prepare them in such a Japanese- style room, but it was for his physical condition. I reunited with several people after 20 years and enjoyed chatting with them.
be reunited with somebody ＜人＞と再会する
[自] 再会する, 再結成する
[他] 〈組織・地域など〉 を再統合する[同意] reunify
[自] 〈国・組織などが〉 再統一する
[C] (家族・同窓生などの) 再会の集い, 同窓会
a family/high-school/college reunion
[C,U] 再会, 再び一緒になること [＋reunion with]
his reunion with his wife 彼の妻との復縁