He entered Seisho High School, and played in a Japan-US friendly match during his 2nd year, along with Taishi Nakagawa and Koji Fukutani.

He came upon Nolan Ryan's Pitcher's Bible, and he will be quoted later on that reading the book prompted him to change his pitching form.

[6] 2013 He pitched 6.2 scoreless innings in his first official match on April 3, and secured his first victory when the Swallows beat the Carps by 4 runs, the first among his fellow rookie pitchers to do so.

[8] His second win came a week later, when he pitched 7 innings against the Chunichi Dragons without surrendering any runs, and gave up only a single hit to Hector Luna.

[9] By mid-season, he pitched his first shutout win,[10] and became the first rookie in franchise history to record his seventh victory before the end of June.

[13] Even though the Swallows finished in the rear, Ogawa gave the fans a reason to celebrate in what has otherwise been a very disappointing season.

[18] Unfortunately, his winning streak came to a halt when a batted ball struck his right hand during a game against Hanshin on the April 18, where he also gave up 4 runs.

[21] Listed at 171 cm (5 ft 7 in), he may lack the advantage of having longer limbs for extra power, but his form has a slower rhythm to it, making his pitches more difficult to time.