It may depend on the instructor. Shotokan, as far as I know, generally doesn't teach many weapons, but like Wado-Ryu, it's big in Japan, and many of the old-school instructors used to cross-train in other martial arts, like Kendo. The other ones, including the various Shorin-Ryu branches, generally don't teach weapons as part of their karate curriculum, but as an additional Kobudo (literally "ancient warrior ways", often used to refer to Okinawan weapons traditions) program. The only karate system I can think of that has a dedicated weapons program is Isshin-Ryu, which includes sai and bo kata.

Also, when the "five main" karate systems are talked about, generally Kyokushin will take the place of Shorin-Ryu, as the "main five" are part of the Japanese tradition. They generally leave out the systems centered in Okinawa. Goju-Ryu is a bit of an exception, because it's also heavily centered in Okinawa, but unlike many other Okinawan systems, Goju was recognized as an official style by the Dai Nippon Butoku Kai during the 1930's. Shotokan (then called Shoto-Ryu), Shito-Ryu, and Wado-Ryu had all registered with the DNBK by 1939, and are therefore "recognized" by the World Karate Federation. I don't believe Kyokushin is recognized by the WKF, but it is an extremely popular style, particularly in Japan. Okinawan systems like Uechi-Ryu, Isshin-Ryu, and the Shorin-Ryu systems aren't widely practiced in "mainland" Japan.

Funny, I know several Shorinryu master instructors that teach weapons as part of the Shorinryu. All Karate styles are basically open hand arts. As such they don't depend on weapons. BUT, many have i9ncorporated Kobudo (weapons) for a long time. Bottom line here is each school and instructor teaches what they want to teach.

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I know of no karate styles that impliment weapons. Karate is empty hand. Some karate schools (not styles) teach some weapons as part of cirriculum.

callsignfuzzy gave you some good info.

I'll only add that many styles don't formally incorporate weapons in them but train in them as a supplement if the student wishes. Also many seniors train in kobudo (see http://en.wikipedia.org/wiki/Okinawan_ko... separately. For instance, I know folks who train in Uechi and Kobudo and hold different ranks in each.

Also in Uechi Ryu we incorporate the use of swords for bunkai in seisan as the roots of the art come from empty handed individuals defending themselves against warriors with swords.

I know that many of the other Karate styles implement weapons, but I read an article that stated that Wado is the only one of the five main Karate styles (Wado, Goju, Shotokan, Shito, and Shorin) that does not utilize weapons of any kind. Is there anyone that practices Wado that can verify this?