What NIL Means in Duel
NIL is a promise to take no tricks at all, for the whole hand. Keep it and you score +100; take a single trick and it becomes -100. In the duel nobody sits across the table to cover your dangerous cards, so every high card you hold is your own problem. And a broken NIL keeps costing you, because the tricks you took still count as bags, 1 point each, toward the next 100-point bag penalty.
Building a NIL Hand in the Draw
Here the duel does you a favour: you choose your cards before you bid, so a NIL hand is built, not dealt. If the first cards you see are low, lean into it. Keep low cards and refuse high ones; a discarded ace or king is gone for the whole hand, and the card you take in its place is usually lower. Just remember that a hand lasts 13 tricks and the NIL has to survive every one of them, so a single high spade you failed to shed in the draw can sink the whole bid.
Evaluate the Whole Risk
A good NIL hand has low cards in every suit, and more than one of them. A high card in a short suit is the classic trap: you must follow suit when you can, so once that suit is led and your smaller cards in it are gone, the high card has to come out, and it may well win the trick. Save your lowest cards for the tricks where you will need to duck. And do not reach for NIL just because you are behind. Make it earn its place: weigh the 200-point gap between making and breaking it against a realistic numeric contract and the current score.