Key legal question
Whether the Schwarzenburg court had jurisdiction over Zurbrügg's counterclaim despite Article 59 BV
Extracted holding
A defendant may assert by counterclaim before the court seized by the plaintiff those personal claims that are materially connected with the original claim; that condition was met here because both claims arose from the same sale.
Extracted reasoning
Federal practice accepts counterclaim jurisdiction under Article 59 BV where there is material connexity. The counterclaim and the principal claim both stemmed from the same purchase contract and the counterclaim could also operate as a defence to the claim.