Apparently YIPIK only opened last year
https://metropolisjapan.com/your-irish-pub-kyoto/
The Pig & Whistle has been open since 1986 however,
http://www.pigandwhistle.beer
The Irish Pub, Field says it was the first Irish pub n Kyoyo... in 2000 :-)
https://kyotofield.com/irishpub_e.html so thats not it either.
Irish Pub Gnome looks like its in a new building, doesnt have a website either same goes for Dublin. Castle West only has a Japanese website but the building doesnt look old enough.
My money is on the Pig & Whistle.