The true disciple does not just master one art form. Following the popularity of martial arts films in the 1980s, Budokan lets you train in four such disciplines: Karate (unarmed fighting), Bo (staff), Nunchakus (two connected sticks) and Kendo (bamboo swords).
Going against three differently skilled trainers, you can practice each technique as long as you like. Within the same technique or even mixing them, one fighter taking one weapon and his opponent another. Which, of course, is the real challenge. Typical rock-paper-scissors effects apply, as range and agility/speed of weapon usage differs significantly.
The final goal, of course, is to compete in the big tournament. Each opponent there has the choice of weapons and the goal is to anticipate how you can beat him. There is a catch, though. Just optimising on one weapon will not lead to success. In the course of the tournament, you can only select each weapon up to four times. So actually, there may be a good reason to select just "karate" early on, assuming that the first opponents may not be as skillful and therefore still be beatable even with a range disadvantage. The opponents hold some surprises as well, suddenly using weapons which aren't even available to you.
Budokan represents an interesting intermediate stage in the development of the fighting genre. Whereas in the 1980s, it was common to have identical or at least similar fighters competing, the 1990s brought freakier and freakier "characters". This game gives the opponents some personal flavour in textual descriptions and then gives them gameplay-relevant variation through the weapons.
Pretty good graphics and animations make Budokan an playable game even today. It's not one of those ultra-fast fighters and it is not nearly as "spectacular" as some other games; rather, it is more of a "fighting simulation", favouring timing and reaction over wild maneuvers.