This is pretty much how I do surprise in AD&D. If the whole group is being quiet (no running or fighting, no bulky armor) there is the normal chance to surprise monsters. If making too much noise, there is no surprise chance (platemail).
If the party is all silent (Elves, successful Thieves, people with Boots of Elvenkind and Leather / No armor) the chance to surprise monsters is +2in6.
Some monsters have lower chances to be surprised. If it can’t be susprised, then no dice. If it has a 1 in 6 chance to be surprised (such as a Ranger) then approaching silently gives it a 3 in 6 chance to be surprised.
Something has to be somehow more sneaky than Silent and Invisible to warrant better than +2in6 surprise. i think certain giant spiders get that ability.
Remember of course that if you’re surprised, the result of the die is how many surprise segments you lose! Which means if that giant spider surprises 5 in 6, and you rolled a 5, you’re taking 5 attacks from that spider before you get to do anything!
I allow multiple backstabs / assassination attempts if the sneaker surprises the victim, kills him with the first blow, and there are still surprised victims left for his subsequent surprise segment. It’s effectively sneaking up and stabbing two or three guards (however many surprise segments they rolled). But stabbing a guy makes him aware of you and you can’t get multiple backstabs on him. In this way it’s possible, though unlikely, for a Thief or Assassin to take out multiple guards on a surprise round silently without raising an alarm, or for a Thief to backstab then make regular attacks on the guy in subsequent surprise segments to take down a really tough guard.
This is pretty much how I do surprise in AD&D. If the whole group is being quiet (no running or fighting, no bulky armor) there is the normal chance to surprise monsters. If making too much noise, there is no surprise chance (platemail).
If the party is all silent (Elves, successful Thieves, people with Boots of Elvenkind and Leather / No armor) the chance to surprise monsters is +2in6.
Some monsters have lower chances to be surprised. If it can’t be susprised, then no dice. If it has a 1 in 6 chance to be surprised (such as a Ranger) then approaching silently gives it a 3 in 6 chance to be surprised.
Something has to be somehow more sneaky than Silent and Invisible to warrant better than +2in6 surprise. i think certain giant spiders get that ability.
Remember of course that if you’re surprised, the result of the die is how many surprise segments you lose! Which means if that giant spider surprises 5 in 6, and you rolled a 5, you’re taking 5 attacks from that spider before you get to do anything!
I allow multiple backstabs / assassination attempts if the sneaker surprises the victim, kills him with the first blow, and there are still surprised victims left for his subsequent surprise segment. It’s effectively sneaking up and stabbing two or three guards (however many surprise segments they rolled). But stabbing a guy makes him aware of you and you can’t get multiple backstabs on him. In this way it’s possible, though unlikely, for a Thief or Assassin to take out multiple guards on a surprise round silently without raising an alarm, or for a Thief to backstab then make regular attacks on the guy in subsequent surprise segments to take down a really tough guard.