It has been my dream since I entered this world, so I am glad I was able to achieve it.

Lotte's Koki Yamaguchi reached the milestone of 30 Home Runs in a season, a goal he has held since turning professional, during the game against Nippon-Ham on the 15th.

Yamaguchi, who hit his 29th two-run home run in his fourth at-bat in the 6th inning, stepped up for his fifth at-bat in the 9th inning with the score tied 6-6 and no runners out. On the fourth pitch, a fastball thrown by Taisei Yanagawa after a 2-ball, 1-strike count, he hit a game-winning solo shot into the left-center stands. This marked Yamaguchi's first career 30-Home Run season, and he became the first Japanese player for the club to reach 30 Home Runs in a season since Hiromitsu Ochiai, who hit 50 Home Runs in 1986.

◆ Long-term goal

"I want to hit over 30 home runs and win the home run title." Since making that declaration at the new player announcement event on December 4, 2018, Yamaguchi's challenge for 30 Home Runs began.

In 2021, his third year, Yamaguchi hit 9 Home Run, including his first professional Home Run. The following year, in 2022, he hit three consecutive Home Run in a game against the Orix Buffaloes on September 22, finishing the season with a team-high 16 Home Run. In an interview on October 19, 2022, regarding what is necessary to hit 20 or 30 Home Run, he emphasized, 'I think it is about finishing off a sweet pitch with a single swing. I think it is about hitting back fastballs and high-velocity pitches.'

In 2023, it took time for the first one to come against the Seibu Lions on April 25, and he hit 8 Home Runs in the first half of the season. In an interview after the first half of that year, he vowed to make a comeback in the second half, saying, 'In playing baseball, I want to aim for 30, and if asked if I can do it this year (2023), I think there is absolutely no way, so as long as I am a baseball player, I want to keep chasing the number 30.' He hit 14 Home Runs that year, achieving double-digit Home Runs for the second consecutive year.

Having hit double-digit Home Runs for two consecutive years, when asked about what is necessary to hit 30 Home Runs in a season again, he provided a self-analysis in an interview on January 23, 2024: 'First, I think it is to keep playing in games consistently. That is the most important thing. I don't think I can achieve those numbers without standing in the batter's box first, and I believe 30 is a number you reach by playing for a full year. I don't think I can achieve it unless I am in the starting line-up from the opening game and can stay in until the end. My technical skills are still not there yet, so I feel I must level up more and more.'

When informed on February 11, 2024, that no Japanese player has hit 30 Home Runs since the move to Zozo Marine Stadium, Yamaguchi expressed his determination, saying, 'That's right. I know that right-handed hitters haven't been able to break that barrier since Seiya (Inoue) hit 24, and I want to work hard to overcome it. I believe Mr. Ochiai was the last one to hit 30, so I want to try to get close to that.'

During batting practice at the Ishigaki Island spring camp that same year, he hit many angled line drives, raising expectations for 30 Home Runs in the 2024 season; however, after securing a spot on the first-team roster that year, he ended up with only 2 Home Runs, his worst since becoming a regular.

In the professional baseball draft held in October of the same year, Lotte selected Misho Nishikawa, an outfielder and right-handed hitter like Yamaguchi, as their first-round pick.

"It's not just this year; with Shingo (Ishikawa) and Aito joining, I feel like players of the same type have been brought in as reinforcements recently, so it's simply frustrating. I have a strong desire not to lose. It's not just the kids coming in through the draft; the competition has been fierce from the start. It's not about who joined, but rather that this year (2024), I didn't do well because I was too concerned about the people around me. I think I'll always be aware of others, but if I can't focus on what I need to do and compete, it will end up like this year again. I want to do what I am capable of doing." (Interviewed on October 25, 2024)

At the end of this year, Seiya Inoue, who had led the team for many years as a right-handed power hitter, retired from active play.

There are many right-handed hitters, and first of all, I believe I won't be able to survive in this world unless my own characteristics are superior to other right-handed hitters. I want to work toward exceeding Seiya Inoue's numbers, and I think that if I don't hit that much, I won't be able to win the regular outfield position battle for Lotte, which is intense compared to any other team. To survive there, I have to polish my strengths and compete with them. I want to work on developing my strengths and doing the things I couldn't do this year (2024). (Interview on October 25, 2024)

In '25, he did not have many opportunities from the start of the season, but in August, he hit seven home runs in that month alone, including hitting a Home Run in four consecutive At Bats, which tied a Pacific League record. In September, he appeared in 13 games and hit no home runs; Yamaguchi's challenge was to consistently hit home runs.

To continue hitting Home Runs throughout the season, he said, "I think the mental aspect becomes important. I think everyone feels this way when they are hitting well, but when you're on a roll, you feel like you can hit anything. When there is tension somewhere or when you start overthinking what you have to do, I think it's hard to get good results. So, I believe how calmly you can stand in the batter's box becomes crucial, and after that, I think it's just a matter of practicing."

Looking ahead to the 2026 season, which will be his eighth year as a professional, he set a firm goal of hitting 30 Home Runs in a season, stating, 'It has always been my goal, so this is the one thing I don't want to change.'

Regarding his desire to hit 30 Home Run he said, "I definitely think I need to work towards that goal, so I want to keep pursuing it without wavering. If I waver now, I'll start to wonder what the point of playing baseball is and what I've been chasing up until now."

Looking at my numbers so far, it's difficult to say I'll hit 30 home runs, but it's my goal and it's been my goal since I joined the team. I won't let that waver, and no matter what anyone says, I don't want to change that.

Although Yamaguchi made the Opening Day roster, he finished with no home runs in 8 games and was removed from the first-team registration on April 19. During his time in the farm league, he adjusted his batting form and became able to hit back fastballs. He seized the opportunity that arose due to Kyota Fujiwara's injury departure on May 12, hitting 12 home runs in the two months of May and June. On July 24 against the Orix Buffaloes, he hit his 16th Home Run, tying his single-season career high, and on July 26 against the Orix Buffaloes, he hit his 17th Home Run, setting a new single-season career high.

In August, he entered a mass-production phase. After reaching his first 20 Home Run season in a game against the Softbank Hawks on August 11, he hit home runs in four consecutive games from the Rakuten Eagles game on August 18 to the Nippon-Ham game on August 21. On August 26, in a game against the Softbank Hawks, he tied Mr. Inoue's 24 Home Runs in a season with a walk-off home run. Then, in the August 27 game against the Softbank Hawks, he cleared 25 Home Runs in a season—tying the record for the most by a Japanese player since the move to Zozo Marine Stadium—stating, 'I was able to surpass Seiya-san's (Inoue) total and catch up to Hatsushiba-san, so next I will do my best aiming for Ochiai-san's total.'

In the match against Nippon-Ham on August 28, he hit his 26th Home Run, the most in a single season by a Japanese player since the move to Zozo Marine Stadium. He hit 10 Home Runs in August, earning the monthly MVP award and becoming the number one batter in the Pacific League for August.

I didn't really think I would be chosen, so I'm happy. I believe that if I can keep this up, those kinds of titles will come into view. I want to make sure this isn't just for a short period, but something I can sustain.

The road to reaching the number '30' was by no means flat. Since entering the pros, I have swung the bat desperately every day to achieve 30 Home Runs. And now, I have cleared that goal of 30 Home Runs. Next is to win the 'Home Run King' title, which has been my goal since turning pro, and then to hit 50 Home Runs in a season, surpassing Hiromitsu Ochiai.

Interview and text by Yuta Iwashita