The facts are out there if you want them
wow, so it is true, so it is also tru that the, correct me if I'm wrong, blacksmiths guild in Japan, did wipe out there recognition for making high quality swords due to the fact that those inccidents happeb in the Tokugawa family? So general, based on what the book described not many people would know to much about there craftsmenship there after.
It also mentioned that Masamune, Muramasa's teacher, tempered swords of pure steel in a way to be considered a master, I wonder if its possible to discover his secrets if Masamune's craftsmenship created extremly sharp swords.
First, the smiths did not destroy their reputation. There are hundreds of working smiths to this day, even more during the millenium of civil wars. Muramasa was considered a brilliant smith in his day, but was also considered insane. This accounts for much of the image of their blades as being evil, given the way of thinking of historical Japan.
Second, yes the Tokugawa had problems with Muramasa, and issued banns on their people carrying them, and this went far in creating the legend of the Evil Muramasa. But, as should be obvious, many samurai were not part of the clan and could carry them, if they could get their hands on them. Muramasa was a skilled smith and his blades are of high quality, which was highly valued in a country at war.
Third, the traditions of forging a Japanese sword are still alive, as witnessed by the annual festival in Seki (a city in the province of Gifu, between Tokyo and
Kyoto-not far from Sekigahara). It is possible to buy modern swords made with traditional techniques, so there is a great deal known about their craftsmanship.
Fourth, Masamune was not Muramasa's teacher. Apart from the fact that they trained and worked in different provinces, they lived in different centuries. If I am not mistaken, the earliest known work or Muramasa was dated 1501, while Masamune dates to the late 1200s and early 1300s. Masamune actually worked before the practice of signing and dating blades became tradition, so there are few works signed by this master. There are some, however.
There is a rumor of one Masamune blade (the Honjo Masamune) somewhere in Northern Calif. Story goes that it was part of the Imperial Family collection, and after WWII they gave it (and 13 other blades) to a police station. The following year the police gave the collection to an Americal soldier (Sgt or General or something) but there are no reports after that. California is an unsubstantiated rumor only.
Hope this helps.