Нужен вариант перевода термина Threshold. В книге это описывается так:
When you take modifiers that should push a difficulty rating past 9, you generate a threshold instead. Each additional point of difficulty instead takes away one success from your final roll. That success never happened — the task was so hard that you just barely managed to complete it. If your threshold takes away all of your successes, your character fails; although he gave a good try, the job was just too tough. Should the threshold remove all of your successes and leave you with any ones on your dice, your character botches. (Watch out, because actions with a threshold tend to botch a lot.) You have to take away successes due to thresholds before you take away successes due to rolling ones, as well. Fortunately, a threshold alone cannot force you to botch. If the threshold removes all of your successes and there is threshold left over, but you didn't score any ones, the roll is still a simple failure.
Occasionally, an action may call for a threshold without modifying difficulty. If's possible to call for an action at difficulty six with a threshold of three, for instance; in such a case, you'd have to score at least four 6s on your roll to succeed at all. This mechanic could represent a task that's not particularly difficult, but that does require a lot of work to accomplish.
Example: Mark Gillan needs to climb up a slippery ladder in the middle of a rainstorm, so that he can get away from a Hermetic pursuer and reach his foci back home. Normally, the difficulty would be a 6 or 7 to climb a ladder in a hurry, but it's stormy and rainy, so the Storyteller rules that the difficulty increases to 8. The Hermetic mage fires off a quick Effect to make Mark slip, and it causes a further modifier of two. Instead of pushing the difficulty to a 10, the difficulty goes to 9 and the task gets a threshold of one. Mark's player rolls his Dexterity + Athletics and scores four successes, but one of them goes away due to the threshold. Mark does a great job of climbing, but the circumstances are so rough that even his incredible feat just manages to get him up the ladder in time!
Я пока использую вариант "Пороговое значение". Но, думается, можно найти вариант и получше.