It seemed to me that this latest issue of Shrapnel was quite heavily leaning on Solaris VII as a setting. I'm sure that part of it was due to which stories were ready to go at which point in time. But while are plenty of stories to tell on the Game World, I'd hope that it doesn't unduly outweigh the rest of the setting in future issues.
Also, while it's not the kind of detail I'd necessarily expect the character in question to necessarily be aware of, I should note that [spoiler]the martial art which would later be labelled as "Karate" was still restricted to the Pechin warrior class in the Ryukyu Kingdom during the Edo period.
In the wake of the Satsuma invasion of Ryukyu in 1609, the Pechin were barred from carrying weapons in public, and thus were obliged to train in unarmed combat only - except in very limited circumstances when the Satsuma domain (in present-day Kagoshima Prefecture) made firearms available for Ryukyuans acting as bodyguards to envoys making the crossing from Naha to Fuzhou (and on from Fuzhou to Beijing) and back again. Karate as such did not spread elsewhere until after the annexation of Ryukyu as Okinawa Prefecture, when a number of former Pechin brought their teachings to the "home" Japanese islands.
So an Edo-period samurai loyal to the Tokugawa Bakufu would most likely not be aware of this martial art - or, if he was, he would likely have considered it beneath his notice, as it was practiced by warriors which had been defeated in battle. Perhaps doubly so, as the Satsuma samurai who had defeated Ryukyu were themselves of a "tozama" domain set below the Tokugawa shogunate itself.[/spoiler]