Once you have inserted a coin into the cabinet of Namco's Japan-only 1988 baseball arcade game, World Stadium, the text "TO START GAME: PUSH 1P OR 2P BUTTON" will appear on the screen (it was the first game from the company to allow two players to play on one credit); you will then have to press either the 1 Player Start Button or the 2 Player Start Button to proceed to the team selection screen as the game's introductory theme starts to be heard from the Yamaha YM-2151. You will then be given forty-five seconds to select one of the U&C League's twelve teams by pushing the joystick up, down, left, and right, before pressing the first button to confirm your choice - and if you had only pressed the 1 Player Start Button, you will now have to select another team for the CPU to predetermine the behaviour of, but if you pressed that 2 Player Start Button, the second player will now have to pick another team to take control of (which is too bad if the first player had chosen the team he wanted to take control of). The game will then proceed to the stadium selection screen as the timer in the top-right corner of the screen continues counting down; you will now have to select one of the game's three stadiums for your match to take place in, which all have different "personnel housing", "grounds", "distinguishing features", and "breadth" specifications:
Once you have pressed the first button to confirm your choice for a second time the game will proceed to the pitcher selection screen, as the timer in the top-right corner of the screen still continues counting down; you will then have to select one of your chosen team's five pitchers (the back views of whom will be displayed upon the screen as you push your joystick up and down to highlight them), and if you had only pressed that 1 Player Start Button, the CPU will create the illusion of randomly selecting one of its team's five pitchers to predetermine the behaviour of (but it will always stop on the third one). All of the 60 pitchers' names have either the Kanji character hidari (左) or migi (右) next to them, which indicates whether they will pitch while facing to the left or right - and the first, second, and third pitchers for each team also have that orange Kanji character saki (先) next to that character, which means "destination".
Once you have pressed the first button to confirm your choice for the third and final time the game will proceed to the team lineup screen, as the song that you had been hearing from the Yamaha YM-2151 since you had pressed either the 1 or 2 Player Start Button fades out; the name of your chosen team's manager will then be displayed on the right side of its logo and under the two Kanji characters kantoku (監督), which means "director". The 96 other players' names also again have either the Kanji character hidari (左) or migi (右) next to them, but this time it indicates whether they will bat while standing on the left or right side of the catcher's plate - and the 50000-, 58000-, or 70000-strong crowd of fans will then cheer from the DAC as all eighteen players emerge and take their positions on the field of your chosen stadium. Once the applause has died out, the view will change to a shot of that stadium's scoreboard...
...as the match opening jingle is heard from the Yamaha YM-2151; the Kōrakuen Stadium's scoreboard has one small orange flag (which is bearing the image of Namco's signature character) on top of it, but the Kōshien Stadium has two. However, both the Kōrakuen and Kōshien Stadiums' scoreboards have clocks (the one on the former is manufactured by "Saiko") on them, which both start at 6:00 and advance as the match progresses, so you should see how long you can make your match last in game time if you'd selected either of those stadiums - and not only does the Mejā Stadium's scoreboard anglicise its name as "Major", but it also has the logo of Namco's secondary US distributor Atari Games on it, given that the original Pro Yakyuu Family Stadium was licensed to them when it was released in the United States as R.B.I. Baseball. An airship with a banner for "PLAY CITY CARROT" (which is an arcade in Sugamo) behind it will also fly over the scoreboard from the right side of the screen to the left whenever the view changes to a shot of it.
The view will now change to a shot of the centre of the stadium's field as the Katakana text purei bōru (プレイボール), which means "play ball", appears on the screen and the game's first main theme starts to be heard from the Namco CUS-30 (to reflect the sounds of the original Pro Yakyuu Family Stadium, this game's two main themes are heard from that Namco CUS-30; however, secondary themes will be heard from that Yamaha YM-2151, when specific players are at bat for each of the twelve teams). The score will be displayed up in the top-left corner of the screen (with that batting team's initial underlined in red) under the number 1 and the Kanji/Katakana text kai omote (回オモテ), which means "front time" - and the statistics of the No. 1 from the first player's team will be displayed in the bottom-left corner of the screen below the team's initial and above the two Kanji characters kōgeki (攻撃), meaning "attack". The statistics of the chosen pitcher from the second player's team will also be displayed in the bottom-right corner of the screen below the team's initial and above the two different Kanji characters shubi (守備), meaning "defence"; the first player must use his joystick to position his batter inside that batting box, and the second player must push his joystick to the left or right to position his pitcher upon the pitcher's mound, then press his first button to throw the ball. He must now push the joystick left if he wants the ball to curve horizontally, down-left to curve vertically, right to shoot horizontally, down-right to shoot vertically, down to fork and up to be a speed ball - and if the other player's team's current batter failed to hit it, the Katakana text sutoraiku (ストライク), which means "strike", will appear on the screen with the speed at which the ball travelled in kilometres above it, as the first of the two yellow lights next to that letter "S" on the left side of the screen turns on. You both then have to repeat the pitching process, but if the other player's team's current batter fails to strike the ball again, that Katakana text sutoraiku (ストライク) will again appear on the screen with the speed at which the ball travelled in kilometres above it, as the second of those two yellow lights turns on; you'll both then have to repeat that pitching process again, but if the other player's team's current batter fails to hit that ball once again, the Katakana text battā auto (バッターアウト), which means "batter out", will appear on the screen (with the speed at which the ball had travelled in kilometres above it), as the other player team's current batter kicks the ground in frustration, then disappears. Those two yellow lights next to the letter "S" will then turn off as the first of those two orange lights next to the letter "O" turns on, and the other player's team's next batter is brought in - who will have different statistics.
The first player must press the first button to make his batter swing and the second button to make him bunt; once he has struck the ball, the view will change to a shot of your stadium's field as it flies up into the air. If the ball does not land within the white lines, the umpires (of which there are six) will hold their arms up and the Katakana text fāru (ファール), which means "foul", will appear on the screen, and it will be counted as a strike - this will also be signified by one of those two aforementioned yellow lights next to the letter "S" turning on, once the view returns to the image you see above. Also, if the current batter hits the ball so hard that it flies out of the stadium, the text "HOMERUN" will appear on the screen, with the current score (the teams are represented by their initial letters, but the Buckaroos have a small "U" after theirs to avoid confusion with the Bravos), the current batter's name and the distance that the ball travelled in metres next to the Kanji text hikyori (飛距離), which means "flying distance", below it as the crowd cheer from the DAC and a dramatic jingle is heard from the Yamaha YM-2151. If the ball landed within the white lines after your chosen team's current batter hit it, and one of the other players on your chosen team caught it as it fell back down to the ground, you will have to press the first button to make him throw it to one of the other players while pushing your joystick up and down to indicate which player you want him to throw it to; once you have done so, the umpires will hold their arms out and the Katakana text sēfu (セーフ), which means "safe", will appear on the screen if the player was safe, or the umpires will hold their right arms up and different Katakana text auto (アウト), which means "out", will appear on the screen if he was out (as that translation suggests, this will also be counted as an out, and it will be reflected by one of the two orange lights next to that letter "O" on the left side of the screen turning on once the view has returned to that screenshot you see above). The radar of the field at the bottom of the screen shows the positions of that other team's players (they are indicated by the moving hats) - and when your team is batting and the other player's team is pitching, push the joystick up and press the first button to tag out a runner on the other player's team who's attempting to steal a base (they can be seen on the left and right side of the screen). Once you have done so, the runner will run out of sight from the left side of the screen as the other player's team's chosen pitcher throws the ball; once your team's current batter has struck the ball the view will again change to a shot of the field as it flies up into the air, but the other player's team's chosen pitcher will then run off the pitcher's mound, and onto the catcher's plate. You will now have to push your joystick to the left and press the first button to make your chosen team's runner start running, then push the joystick up, and press the second button to make him run back again - and once three outs have occurred, the view will cut back to a shot of your chosen stadium's scoreboard as an organ-like jingle (which is different for all three stadiums) is heard from the Yamaha YM-2151 (the Kōrakuen/Kōshien clocks will also have advanced).
It will now be the first player's turn to pitch, and the second player's (or the CPU's) turn to bat; the lights that were formerly located on the left side of the screen will also move to the right side of the screen as a result of this. The score display will also have the initial of the second player's team underlined in red, and the Kanji/Katakana text above will now read as kai ura (回ウラ), which means "back time" - and the game will continue until a preset number of innings or minutes (depending on what the arcade operator has set the "INNINGS" setting in the game's option menu to) have been played (whichever comes first; you'll then have to insert another coin and press either Start Button within 15 seconds, to continue your game). Once nine full innings have been played (or the losing team are down by ten runs in the bottom of any inning), the Katakana text gēmu setto (ゲームセット), which means "gameset", will appear on the screen, as the match's "victory" theme starts to be heard from the Yamaha YM-2151 - and the view will then change to a shot of a player from the winning team standing on a podium, while being interviewed by a news reporter and photographed by eight cameramen. The winning team's logo and the two Kanji characters shōri (勝利), which means "victory", will then appear on the right side of the screen (along with the winning team's name in Katakana and two exclamation marks) as the shot becomes the front page of a newspaper (with a Kanji/Katakana title Nikkan Namuko Supōtsu (日刊ナムコスポーツ), which means "Nikkan Namco Sports"; the match result will appear at the top of the screen under the Kanji/Katakana text kyō no kekka (今日のけっか), which means "consequence of today", along with the number of runs that both teams scored, during the top and bottom of each inning. The match statistics, along with the Hiragana/Katakana text dēto ha itariantomato (デートはイタリアントマト), which means "dating Italian tomatoes", will now appear at the bottom of the screen (however, if any statistics are higher than 70, the letter "X" will be displayed instead) as the three-script text kyō no sai-dai no hōmuran (今日のさい大のホームラン), which means "the biggest home run today", appears on the left side of the screen with one team's initial and name of the player who hit the furthest home run and its flying distance in metres below it (however, if no home runs were hit during the course of that match, the Hiragana text nashi (なし) will appear instead), as the Hiragana text sho sho shōri ha biku tori i yatta ze kon'ya ha oi waida (しょっしょっしょうりはびくとりいやったぜこんやはおいわいだ) appears below it. The text "GAME OVER" will then appear upon the screen as the aforementioned "victory" theme fades out and the game will go back into attract mode.