You must throw a no-hitter using any number of pitchers (minimum nine innings, Pro difficulty or higher). To have a better chance of achieving this, do the following: start by adjusting the "Difficulty" tab to "Pro", then go to "AI Batting" and adjust the following all the way to the right: "AI Take Strike Overall", " AI Take Strike Ahead", and "AI Take Strike Behind". This will cause the CPU to watch many strike threes. Next, adjust the following all the way to the left: "AI Take Ball Overall", "AI Take Ball Ahead", and "AI Take Ball Behind". This will cause the CPU to swing at borderline, slightly off the strike zone pitches. Next, adjust the following to the left "AI Skill", "AI Contact", and "AI Power". This will cause the CPU to hit the ball weakly, if they make contact at all. Finally, go the the "Human" tab and adjust the following all the way to the right: "Infielder Speed", "Outfielder Speed", "Infielder Reaction Speed", and "Outfielder Reaction Speed". With the contact and power of the CPU all the way down, if they hit the ball, they may either weak flares to the outfield and having the your speed up will help catch a few balls that may drop in. Also, infielders or outfielders sometimes run in the opposite direction of a batted ball. This allows you to recover and get some grounders or fly balls that may sometimes sneak through or drop in. Once all the adjustments have been make, check the original tab that read "Pro" and make sure it is now "Custom-P." Since you need to be on at least Pro to get the achievement, Custom-P(ro) is acceptable and will allow you to earn it. When pitching to the CPU, stay on the inside and close to the corners. Pitches on the outside corner tend to be hit up the middle for hits. You will improve your odds by pitching inside.