They are very superficially similar, and very different at the same time. They both contain two man sparring with designated target zones. The Fencing guys where a face mask to protect the face, but are mostly armorless otherwise. The kendo folks where somewhat more armor. The fencing guys tend to thrust a lot, the kendo guys do a lot more cutting.

What you are asking is a lot like comparing basketball to soccer. They have a little bit in common, like balls, nets players, a general goal of getting the ball in the net, but otherwise they are VERY different.
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