At the King's court, duels are sometimes used as a way of settling disputes. However to avoid too many injuries the king has decreed that combatants must use only one finger as a weapon. Any finger may be chosen.
This is the standard hand position.
Rules
It's somewhat similar to fencing but with one finger.
Armour is banned. Only light, modesty-preserving clothing may be worn.
Nothing can be worn on or held in the hands. Fingernails must be short.
Once you have chosen which finger to use, you must stick with it until the end of the fight.
The loser is the first to submit or be fatally injured.
Question
Sir Barrard really wants to kill his opponent Sir Forgyle. Can he do it, even in theory? Can he do it with a single blow or would it take several? What are Sir Forgyle's best defence moves to preserve his life?
NOTE
These are normal humans in the sense that no magic or superpowers are involved.
You can strike any part of the opponent's body with your chosen finger but you cannot use any other part of your body as a weapon. If you get stuck in a clinch (as in boxing) the referee will separate you.
Note that honour and chivalry are very important in this society. Anyone who was seen to behave in an unsportsmanlike manner would be declared the loser and even ostracised. Referees enforce correct behaviour but the king's decision is final.
NOTES ON DEFENCE
You are allowed to block/parry the opponents finger with your finger as in fencing. You must not strike the opponent's finger with any other body-part.
New rule
You must keep your free hand flat on your body at all times. You can form a shield for any part of your body by sliding your hand there without lifting it off your skin. If in doing so, you push aside your opponent's finger as it is about to strike then that is allowed. In the event that your sliding hand damages the opponent's finger that is not counted as a blow and is allowed.