Pachinko machines and pachislo machines, which are used in pachinko parlors, are generically called “yugiki” (game machines). While gambling machines are designed to cause the result of the play to depend solely on chance, the relevant law stipulates that game machines or yugiki must require players to obtain some “skills” to win games. In the case of a pachinko machine, the player has to operate the Handle (knob designed to shoot balls) to guide shot balls in the desired direction. Basically, pachislo machines are designed to require the players to push the stop button to stop the reel, thus they need to obtain some “skills” to win games, as in the case of pachinko machines.

According to legal definition in Japan, pachinko and pachislo machines are officially called “pachinko yugiki” (game machines) and “kaidoshiki yugiki“ (reel-type game machines), respectively. In addition to these game machines, there are some other machines, such as “Arrange Ball” (pinball arcade game) machines, “Jankyu” (game combining mahjong and pachinko) machines, and “Smart Ball” (Japanese-style pinball game) machines, all of which are rarely seen nowadays. There were “Palot” pachislo (slot game using pachinko balls) machines; however, they were discontinued a long time ago.

The original type of pachinko machine had a pachinko board filled with equally-spaced pins and holes, on which shot balls cascaded down. After more than 80 years of modification in successive periods, the majority of pachinko machines are now equipped with an LCD display unit. The Fever pachinko machine (Jackpot pachinko machine) debuted about 40 years ago. Since then, the following system has remained unchanged: if a shot ball goes into the winning pocket called the “Start Chucker” (start gate, rotation is started for main digital), the LCD, etc. starts providing many different animations, an “oatari” (jackpot) is hit if a winning number/pattern combination is achieved after the end of such animations. However, many of the features, such as the animation presentation system, the number of balls you get for an oatari and successive generation of oatari, have changed considerably. Oatari probability differs from model to model. Furthermore, the frequency of occurrence of a game feature called “Probability Fluctuation”, which means the oatari rate just after the achievement of an oatari increases, as well as the number of successive occurrences, also varies from model to model.

On the other hand, pachislo machines use tokens in stead of balls. With pachislo machines, you try to get more tokens mainly by achieving “Big Bonuses” (large amount of winning tokens) or “Regular Bonuses” (small amount of winning tokens), which can be obtained by achieving number/pattern combinations. Some pachislo machines are designed to allow you to get additional tokens using Koyaku (winning combinations other than Bonuses) patterns such as Bells or Watermelons. In addition, some other pachislo machines have both features.