Four cards. One clear explanation.

Give the example its context

Select the trump suit and the player who led. Choose one unique card for each fixed seat. The tool derives the led suit from the leader’s card, then identifies the winning card. North–South and East–West are the example partnerships.

Keep the boundary in view

This compares the four entered cards only. It cannot check following suit from a player’s unseen remaining hand, recommend a strategy or simulate a complete game. Example outputs do not save into the scorebook.

Try the presets

Change one condition at a time and explain the result aloud. The default example below shows a low spade trump beating higher hearts. Without JavaScript that illustrated result remains readable.