Closed community of Japan MOF and Customs

I was in a evening party on May 16th (Fri) at luxurious hotel in Akasaka, Tokyo.
The party was annual party of Japan Tariff Association (JTA), the people gathered there were Japanese MOF and Customs people, and from companies involved in international trade.
The total number of people there were approx. 200, I guessed.
I was first time to join this party, as I set up Tokyo office for the US law firm last year.
The impression of the party is that, all people there were same "tribe".
All Japanese male with Senior age, probably 60-70 years old. No women! No foreigner!
The word "Diversity" is meaningless in such community.

I find young guy who is from JTA, he said 70-80% of people there are from MOF or Customs.
Even from private companies, the participants are actually ex-MOF or ex-Customs who now belong to private sectors as advisor after long years of service in government. We call it "Amakudari", which means appointment of a retiring government official to an important post in an industry controlled by his former ministry. Most of people despise "Amakudari" as it is a vested interests of senior government officials and such peoples are generally not competitive.
Namely, this party is alumni party of Japanese government officers. People there seem to be known each other by group and by group. For me, most of senior guys there look like same face and had same dark suit.

Although I'm typical Japanese male, I felt I was like alien there, probably I was only manager from foreign company. But luckly, I happen to find nice guy who is from JTA, manager of planning department. He is close to my age, and very energetic and thoughtful, has many idea to positively activate Customs community, I really enjoyed chat with him. The MOF and Customs officials community is still so closed and dominated by old generation, I was so happy to find an able manager in JTA last night.