Just to see if others understand this like I do: In a check like an Attack, per the bottom of page 23 in the Core Rulebook, Opportunities are allocated BEFORE the outcome of the attack is determined and thus also, before fatigue damage or critical hits are dealt.

That means that it is possible to impose an effect on an opponent in the same attack as exploiting that effect for e.g. more damage.

A few examples:

- The Hunting Cat has a bite attack of Deadliness 9 and the ability to deal the Disoriented condition to an unaware or prone target with an Opportunity. It also has the ability "Disoriented targets cannot defend against damage dealth by a hunting cat." Thus, a hunting cat attacking an unaware target can make an attack and, with 2 successes and one Opportunity, can first impose the Disoriented condition on the target and then, since the Disoriented target cannot defend, deal a Critikal Strike of Severity 9 in the same attack. Ouch.

- E.g. a Kuni Purifier with a Tetsubo of Earth could make an attack, spend 1 Opportunity on the Iron in the Mountains Style kata and, if the targets fails its Fitness check, deal extra damage equal to their Earth ring for this same attack, since Tetsubo of Earth do more damage vs. Prone targets, and the target is prone when dealt the damage.

- A bushi with Heartpiercing Strike kata could make a Fire stance attack and spend Opportunities to increase the TN of the next check to resist a critical strike. That roll with be resisting the very same attack, because this is an Attack action, and the Opportunities are spent before the Critical hit is dealt. Thus, the TN of the Resist roll is 3 (Air 4, Water 1) +Opportunities spent. And if the TN is not reached, the Critical Hit severity isn't lessened at all, in contrast to e.g. how spending Opportunities in Razor-Edged would work. Partial successes count for nothing. Ouch.
(Of course, on the other hand, the Razor-Edged quality can increase the Severity beyond Deadliness + Bonus Successes, something this use of Opportunities doesn't do.)

All on the same page?

37 minutes ago, Harzerkatze said:

Just to see if others understand this like I do: In a check like an Attack, per the bottom of page 23 in the Core Rulebook, Opportunities are allocated BEFORE the outcome of the attack is determined and thus also, before fatigue damage or critical hits are dealt.

That means that it is possible to impose an effect on an opponent in the same attack as exploiting that effect for e.g. more damage.

That's correct. Unless the effect of the opportunity requires success (which isn't calculated until a later step) it's applied then. So in theory you can do something nasty and then capitalise on it.

Using a fire opportunity to apply strife whilst using Iaijutsu Cut: Rising Blade would potentially do this, too, since you can't defend if compromised.

Note that in the case of the hunting cat, you still need to have snuck up to range 1 of your victim first (or knocked them prone).

Ultimately, spending 1 opportunity for a disoriented/cannot defend effect is only a slightly-easier-to-achieve version of spending 2 for a straight up critical strike (which it can do as an adversary-level opponent) - and in that case you suck the critical strike and the fatigue.

38 minutes ago, Harzerkatze said:

- A bushi with Heartpiercing Strike kata could make a Fire stance attack and spend Opportunities to increase the TN of the next check to resist a critical strike. That roll with be resisting the very same attack, because this is an Attack action, and the Opportunities are spent before the Critical hit is dealt. Thus, the TN of the Resist roll is 3 (Air 4, Water 1) +Opportunities spent. And if the TN is not reached, the Critical Hit severity isn't lessened at all, in contrast to e.g. how spending Opportunities in Razor-Edged would work. Partial successes count for nothing. Ouch.

True. But now you're talking about getting three successes (to succeed) plus a bunch of opportunities to get the effect you want. Heartpiercing strike is a devastating kata because it's proportionally not easy to pull off and it has a downside if you bugger it up to boot.