Kaschlan
... that the card game of Kaschlan, named after its top trump, became so popular that it was used in the Prussian idiom "my stomach's playing Kaschlan with my bowels"?
... that the card game of <b id="mwCi8"><a href="./Kaschlan" id="mwCjA" rel="mw:WikiLink" title="Kaschlan">Kaschlan</a></b>, named after its top <a href="./Trump_(card_games)" id="mwCjE" rel="mw:WikiLink" title="Trump (card games)">trump</a>, became so popular that it was used in the <a href="./Prussia" id="mwCjI" rel="mw:WikiLink" title="Prussia">Prussian</a> idiom "my stomach's playing Kaschlan with my bowels"?