I've been out MV-ing.
The caption of the post is not quite correct and therefore the content. It should actually read 13 six cylinder bikes.
Having been a follower of MV Agusta since the Agostini reign of the 1960's and 70's the Italian company has been a leader in technology development, especially in the time period we are discussing here. And in all respect to Mr. Honda and his monumental effort to get his 6cylinder bike it's first outing at the Isle of Man about 1966 , MV had already built a double over head cam 500 6 cylinder bike in 1957.
Read about it here
Also -there are some nice photo's of the Laverda museum ( up for sale ) in the Netherlands
www.motorcyclenews.com/news/2017/may/lav...otorcycles-for-sale/
www.motorcyclespecs.co.za/model/Classic%..._350_sixcylinder.htm