In the episode Viking vs Samurai, their were were mulitple historical inaccuracies. I'm going to point some of these out. For one the weapons. The Kanabo and Naginata were not used by samurai. The Kanabo has little to no evidence of it's use by samurai, also the one used was ridiculous, a 35lbs club would never of been used by anyone, that is to heavy to realistically be used. The Naginata was used mostly by the wives of samurai to protect themselves when their husbands were away, Samurai would actully use a Spear in battle. Also the Viking didn't have his bow, which was historically more powerful than the Yumi, because the wood used for their bows was a naturally exsisting composet.
Also the chainmail shown on the show is actully reenactment butted mail, not historaclly correct rivited mail. No one would use butted mail becasue it fell apart so easily, yet took a great deal of time to make. Properly made chainmail can stop arrows and stabs, In the epsioded Viking vs Samurai, the final sim shows an arrow punching through it, in Willain Wallace vs Shaka Zulu it shows a spear pirecing chianmail, this would not happen with rivited chainmail. I've seen chainmail, accurate chainmail, stop spear thrusts and arrows, both in real life and Historic documentarys on Vikings.
In Willian Wallace vs Shaka Zulu, Shaka's sheild was not accurate to what real Zulu sheils would be, they were actully multiple layers a cow hide, and was much stronger than than the one shown.
in Pirate vs Knight, they gave the knight a crossbow, Knights didn't use crossbows or bows. They unites who did use them were specility unites.
All in all the show is a real hit and miss affair, some of the stuff they show is correct and other times the ycompletly missrepresent a warrior. This resulted warriors Like the Viking and Shaka not getting a fair chance. Also some of the shows "experts" are not experts, excepting maybe Barry Jaconsen.