What time Sunday?
I might be in Konstanz at the weekend; if the session was early in the day I’d love to nip in.
The session "officially" starts at 19:30. It’s almost every Sunday, but especially if some of the core players are on vacation it may be cancelled. Send me an e-mail to firstname.lastname@example.org if you plan to visit the session at a specific Sunday, so i can tell you if the Session has been canceled or not. There is some additional info at http://irishmusic-konstanz.de/html/session.html.
Re: Shamrock Irish Pub
The pub’s website has the start time as 8.30pm.