This tactic uses an open-ended question. The term “Krunch” was coined by Chester L. Karrass, procurement man of the 1960's and in-flight training magazine workshop darling into the 21st Century. This is a stylized version of the “Gaps to be Filled” tactic.
Karass uses terms such as, “You’ve got to do significantly better than that.” Expecting, the target to negotiate against themselves.
The way to counter this is identical to countering the Gaps to be Filled tactic. Also, you can rely on your personal relationship with the negotiator to support candidness. For example, you might say, “You mean to tell me all other bidders are offering this exact time, place, manner, and level of service?” Saying "I have nothing else" and "no" puts a boundary on the Krunch. We love Chester.