Interrupting spell-casting

[tavis]

In your game, can a spell be interrupted before it's finished casting? How do you decide whether or not the spell caster is able to get it off or not?

[jcstephens]

In my game, spells are cast by tracing a sigil in the air or on the object being ensorceled (they glow for a second or two after being cast, as a special effect). Sort of like a hand grenade, just pull the pin and throw. Whoever has the initiative gets to go first, which means that wizard duels are more a question of who can ambush who first.

[Zulgyan]

In my game, if you win iniciative and hit the wizard or cleric before he gets to release the spell, you spoil his casting with the hit.

All spell casting starts at the beginning of the round, so you need not to get hit in order to complete the invocation.

Pretty much the standart I believe.

[tavis]

So you're saying that spell casting gets declared before rolling for initiative, Zulgyan?

Do you resolve the combat round in phases? What phase does spell casting begin, and when does it end? If two casters are throwing spells at one another, whose goes off first?

[Zulgyan]

Oh, yes I do.

I follow the same sequence of D&D B/X.

It's:

1. Players declare intent of action (can be as vague as "I attack" and the specifics can be given later). If spell, they declare which spell.
2. DM secretely decides actions for monsters/npcs.
3. Each side rolls 1d6.
4. Side that wins does all actions, with adjudication by the DM.
5. Side that lost iniciative follows.
6. Morale.
7. go back to one.

So if a side with a wizard loses, and the wizard gets hit, his spell is spoiled. Casters begin to invoke the spell at the beggining of the round.

That's what I usually do. Sometime I don't use iniciative if I don't need it. I just declare which action goes first based in common sense.

[philotomy]

In my game, spellcasting is interrupted by being struck by a missile, et cetera, but also by engagement in melee. That is, if a Fighting Man can just get close enough to engage the Magic User, that's enough -- he doesn't have to actually hit him. (This is from Swords & Spells.)

T. Foster recently pointed out that a strict application of this rule will nerf evil cleric spells (e.g. Swords & Spells gives a range of "touch" for Cause Light Wounds). I've been allowing evil cleric spells to be used at range (much like the example of Finger of Death). Another approach would be to simply allow spell-based exceptions (i.e. this spell is designed to be used in melee, thus it isn't interrupted by melee engagement).

Edit --

More details the system I use can be found, here:

Full Combat Sequence
Condensed Combat Sequence

[tavis]

Philotomy, I like the look of the simple combat sequence. Let me repeat it below for clarity before asking some questions about it:


1. Both sides roll 1d6 for initiative; high roll wins.
2. Winning side fires missiles, starts spells (and finishes spells of level 1-2)
3. Losing side fires missiles, starts spells (and finishes spells of level 1-2)
4. Both sides move
5. Spells that were started in 2-3 take effect; archers who didn't move and haven't been engaged in melee may fire again
6. Melee

Is it true that there's no way to interrupt a caster throwing a spell of level 1-2, since they both start and finish their spell in phase 2 or 3?

Is it true that the only way to interrupt a caster throwing a spell of level 3+ (resolves in step 5) is to hit them with missile fire (step 2 or 3) or move to engage them (step 4)?