Some "K" Words: "Kibosh" 2

       Does "kibosh" go back to Yiddish “kye” as “18,” “bosh” as “pence”? 
      
       “It’s said that bidders at small auctions, put the kibosh on other bidders, forced them out, by jumping their bids to eighteen pence.”  Leo Rosten puts the word in his book The Joys of Yiddish, only indicating, after exhaustive consideration, that he’s not very happy with any etymology, including Yiddish.
 
       I want to believe that it came over to America as “death cape” with Irish immigrants as my friend Marvin said, but I’m afraid I have to put the kibosh on that one too.  I reluctantly resign myself to the  exasperating, universally agreed upon source in all my principal references:  “origin unknown.”