Did Saber ever learn Eastern fencing styles before meeting Shiro? I don't play Fate/Stay Night visual novel, but I'm quite a fan of the anime series, mainly because of its historic sense — with those people from the legends and all. However, I've spotted a flaw — albeit not a fatal one — and it bothers me a bit.

In the universe of Fate/Stay Night, Saber is the legendary King Arthur (or rather, Arthuria) Pendragon that comes from Celtic legends. With such a background, I expect her to use a Western fencing style (though the term is not exclusively used in the Western world the way that word means today).

While Arthuria did, in fact, fight with the Western fencing style throughout the anime in all her real battles, I've noticed that, especially in her training with Shiro, she used an Eastern fencing style.

Was it ever explained in the visual novel if she learned the Eastern fencing style before or anything? The age in which she lived in was all but related to the easternmost part of the world.
In the Fate/SN world, heroes learn everything they need to know about about age they were summoned in. Knowledge such as how to operate common machinery, customs, and language are automatically learned during their summoning. As an example, Saber learned how to ride motorcycles in Fate/Zero. Motorcycles did not exist in her age, but she knows how to operate one nevertheless. This is also the reason why there is no language barrier between Saber and Shirou.

As Kendo is a common sport in Japan and a martial art involving swords, Saber could have learned this particular Eastern fencing style as part of the Japanese customs she had to learn from her summoning.