Tedronai is correct. See YS276 right column second paragraph and YS277 left column fourth paragraph. It's simply a "landmine" set up as a movement block instead of an attack.
AND
Not sure I'm understanding but, it was the landmine which paid for multiple zones, not the ward itself. (If I have misunderstood your point please correct me.)
Okay, somehow I misunderstood that the persistent block vs. movement was the result of a 'landmine' so it makes a bit more sense now. Not sure that I'd require a trigger though, since forcing oneself into/through the Ward does seem to me to be an automatic implied trigger anyway. Having a special condition and some sort of symbolic link for the caster so that they aren't effected by the zone-wide blocks against movement would seem sensible though.
Looks decent. I won't use an 8 shift basic ward against the PCs - find it kinda cheesy. (It's why I limit NPCs to Lore for any given effect.) But there's nothing preventing it in the book.
Actually, that Ward is a defense around one of the character's homes, and the Ward itself has already been damaged once.
Yep! Temporarily at least...and with the attack reduced by the power of the ward. Taking the ward down permanently means beating the entire ward by 4+.
AND
Per YS276, shifts are reduced by the block and you can either use excess shifts against a target inside or against the ward itself. The ward, not the block. So it will take a bit more than two attacks to take the entire ward down.
I agree, but here is my take on it. From my reading of YS276-277, the 'strength' of the Ward is determined by the strength of the Block, landmines, selective conditions and extended duration all add to the overall Complexity when casting the Ward, but don't make it stronger.
So, lets go through an example here of a Rote evocation attack from a caster with Great (+4) Conviction and Discipline where the attack doesn't make use of any specializations or focus items.
Again, the Ward has a Block strength of Great (+4), which gets treated and potentially bypassed just like a normal block per YS276. Assuming the attacking caster rolls a +0, their net attack works out to Great (+4) due to their Discipline, which is a match for the strength of the Block: Great (+4), but ties go to the attacker so that counts as a 'hit' but with +0 shifts of success, and per YS210 the weapon strength, or in this cast the power of the evocation gets added to the total shifts of success for a net of +4 shifts of success. If the attacker chooses to apply all 4 shifts of success to attacking the strength of the Ward, that Ward quickly goes from Great to Mediocre and the Block strength is effected as well. At Mediocre the Ward is still there, but no longer presents much of a barrier, though any special conditions and/or landmines would remain in effect. A second evocation attack from the same caster and of the same strength would automatically bring the Ward down, since they would need to meet or beat a Mediocre targeting roll, and then do a minimum of 4 shifts of damage to the Ward itself.
I agree with almost everything you said Vargo. However, I generally put thaumaturgy exchanges at minutes or even hours per exchange. Unless we're talking thaumaturgy at evocation speeds at least.
So it's significant if thinking in combat terms.
I myself generally set non-combat Thaumaturgy exchanges to 15 minutes per change, about the length of a non-combat scene usually.
-Cheers