Bridge & other card games/dangerous opponent
How does one find out when, and which, opponent will be dangerous in playing a contract?
Thank you very much and find this form very helpful
A dangerous opponent is one that declarer does not want to gain the lead because if he does he can do potentially harmful things. For example, if you are in a notrump contract and one opponent has set up his long suit and can cash enough tricks to set you if he gains the lead while the other opponent has no more cards in that suit and therefore cannot lead it then the first opponent is dangerous and his partner is safe.
Another example is if one of your suits consists of Kxx in dummy and xxx(three small cards) in your hand. Your left hand opponent is dangerous since if he gains the lead, he can possibly lead through the unprotected King and if the Ace is in the wrong place, the opponents could take 3 tricks in that suit (maybe more in notrump). Right hand opponent, on the other hand, is safe since if he leads the suit then your King will be sure to take a trick. Notice that it is not the opponent with the Ace that is dangerous but instead it is the opponent who is in a position to lead through your unprotected honor.
Another situation where an opponent could be dangerous is if, should he gain the lead, he could give his partner a ruff.
The following article is instructive.