A Fastball

"One fastball. Until next spring, Kōshū, you only need to hone one fastball." Coach Ninomiya solemnly held up one finger.

"Then can I still play as a pitcher?" Kōshū asked cautiously.

"Haha, of course you can play. But you can only throw fastballs. Even with just that one pitch, you need to consider adjustments to velocity, spin rate, spin axis, and accuracy. Half a year may sound like a long time, but if you really want to throw one fastball well, there still isn't enough time." Coach Ninomiya pulled out a sheet of paper from the mountain of books and documents on the table. The front seemed to contain an English paper. He casually flipped it over and scribbled furiously across the back.

"Although I'm a coach now, I used to be an orthopedic doctor, and before that, I was a medical school lecturer. I'm not the kind of coach who spends all day shouting meaningless motivational slogans. Kōshū, you can play professional baseball until you're forty. For the sake of the decades ahead, spending just half a year building your foundation is absolutely worthwhile." With that, he used two fingers to slide the A4 sheet directly in front of Kōshū.

"Kōshū, this is my duty as your introductory coach, and it is also your duty."

Kōshū looked at the wildly scrawled handwriting before him and barely made out that it was a task list arranged along a timeline.

Fortunately, Coach Ninomiya had not expected him to decipher a medical lecturer's handwriting and explained it from top to bottom.

"First is a physical examination. You need to undergo an X-ray Examination to check your Bone Density and projected height. This checkup will take place once every six months. The pitching coaches will probably create a physical profile for you in the next few days, and they'll update your physical measurements every week—height, grip strength, pushing strength, and so on. This is to verify the effectiveness of training and to prevent chronic injuries caused by overtraining."

"Second, pay attention to your diet and rest. This is the target for six months from now." Coach Ninomiya pointed at the number on the paper.

"76 kilograms?"

"You're only 67 kilograms now, right? After the first week of training, many children lose around one or two kilograms because their diet can't keep up. Most of them are between 1.6 and 1.75 meters tall. Kōshū, you're already 1.82 meters. If you get any thinner, there won't be anything left to protect you. So for the next half year, you need to increase your food intake by around 10% every month compared to the previous month. Ten percent is roughly the equivalent of eating one extra chicken drumstick per meal. As for food proportions, weekends and holidays are easier—we'll arrange plenty of meat for you. But when you're at school, eat more meat, eggs, and dairy. Once we have the X-rays, you may need vitamin D supplements. I think Hui Li has already told your mother about our club's philosophy."

Kōshū nodded, recalling how his mother and Mr. Sasaki had discussed buying a large refrigerator at the dinner table yesterday.

"Next is rest. People your age really have it good. Even if you don't nap at noon, as long as there's a ball to play with, you can stay energetic all day. Even if you don't rest well one day, you can recover quickly. It may look like proper rest and relying on your body to recover are no different, but that's an illusion. If people had something like a health account, proper rest would be depositing money, while relying on your body to recover would be constantly spending it. So while eating properly, make sure you rest properly as well."

Then his voice dropped to a mumble. "The numbers after that are the weights you need to reach each month. That's the pitching coaches' task. Let's move on."

"Third is the process of honing that one fastball. Kōshū, listen carefully to this. The fastball is the foundation of every other pitch, and among all its attributes, velocity is the most fundamental. The first two points I mentioned were all for increasing velocity. As for the specific training plan, you can ask Coach Yoshioka. Spin rate, meanwhile, is the basis of a fastball's power. Even among professional players, fastballs with different spin rates feel different to batters." Coach Ninomiya paused. "That's one reason behind what people call a fastball with late life."

"High and low spin rates... Are you sure you want to explain that to a middle schooler?" Kōshū pointed at himself, amusement in his eyes.

"Haha, you'll understand at the next study session. Since you love this sport, you should all learn the knowledge related to it as well."

Coach Ninomiya paused for a sip of water. "Spin rate is the speed at which the ball rotates. At the same velocity, a high-spin ball not only drops less from the Pitcher's Mound to Home Plate—meaning it stays straighter and flatter—but when the batter hits it, they face not only the force of the direct impact, but also the force of the ball's powerful rotation. That makes it hard to get a clean grip on it. If a pitcher can control spin rate, then even the same fastball can produce different effects."

He pointed again at the numerous tasks listed after the third item. "These include fine-tuning your mechanics as your body grows and training the sensitivity of your fingertips. You can ask Coach Yoshioka directly. This is something we've been researching for the past year. The changes have been especially obvious with ChaiZaki. He'll be returning to the team soon, so you can talk with him."

Perhaps to keep Kōshū from feeling burdened by too many tasks, Coach Ninomiya skipped over a mass of illegible scribbles and pointed directly at spin axis. "Spin axis refers to the angle between the ball's axis of rotation in the air after release and its intended direction. For a fastball, the direction is very clear. The ideal state is for the ball to fly straight into the catcher's glove without losing energy because its spin axis turns left or right."

"Determining spin-axis deviation requires professional equipment, and we don't have that yet." Coach Ninomiya tapped the table. "My son works as an assistant pitching coach in American professional baseball. If they get anything new over there, I'll get my hands on it as soon as possible."

Kōshū obediently nodded, though he felt somewhat uneasy inside.

Coach Ninomiya sighed.

"Kōshū, it's really fortunate that you joined the team at a time like this. Your spin axis is extremely clean."

"But I only threw a little over thirty pitches yesterday..." Then he remembered the cameras set up on both sides of the Bullpen, including behind the pitcher and behind the catcher. "So that was why. I thought every Bullpen had cameras set up."

"Haha, we set those up to measure spin rate. I didn't expect to see something even more interesting. Kōshū, your accuracy is incredible. According to our analysis, part of the reason is that your spin axis is so clean. When you want to throw to a certain spot, there's basically no movement caused by spin-axis deviation."

"Then would there be a problem if I learned Changeups?"

Coach Ninomiya did not answer immediately. He considered it for a moment. "In my many years of experience, there shouldn't be a problem. But that is something to consider next year. Right now, we still have many questions to study—for example, just how much more threatening a pure fastball like this can become to batters."

Finally came accuracy.

"Accuracy seems to be your strong suit. Tomorrow morning, we need to assess the limits of your accuracy before deciding on your subsequent training tasks."

With that, every plan on the paper had been covered. "As we learn more about your physical condition, these plans may also change."

Coach Ninomiya didn't seem to recommend that I play positions other than pitcher, Kōshū thought.

"Kōshū, let's end our discussion here for today. Please bring your younger brother over as well. I saw him waiting for you in the Indoor Training Field."

After thanking him, Kōshū closed the office door. Only after walking a few steps away did he gently breathe out all the air in his lungs. His mind had been filled with so much information. It seemed the coaches also hoped to gain some training experience from him, but Kōshū understood their sincerity. He was actually quite looking forward to seeing himself six months from now.

Compared to the excited Kōshū, Lang Zhi, who had remained in the training field batting, felt somewhat unbalanced. There were already six people on the team practicing at shortstop. Unlike Kōshū, he had no outstanding talent in any particular skill. The only thing he could say for himself was that he had good coordination, which did not stand out much among a group of exceptionally talented shortstops.

I kind of regret letting that slip today. Damn it, the comparison of the brothers' abilities I imagined before might be coming soon. More importantly, he stopped swinging his bat and instinctively began calculating the money involved. It's so expensive. Besides the one-time registration fee, there are monthly fees, meal costs, damaged clothes, damaged equipment, and extra nutrition at home.

"Ever since we said we wanted to play hardball, Mom and Dad have really gotten serious..." Lang Zhi muttered, not noticing the hand reaching from behind to cover his head.

"What do you mean, gotten serious?" Kōshū pressed down on the shorter boy's head and gently shook him. "Don't overthink things. Why not use the energy you spend overthinking on training hard instead?"

"Tch." Lang Zhi jumped aside. "Don't act like you know what I'm thinking."

"Fine, fine. Oh, right, Coach Ninomiya wants you in his office." Kōshū pointed upstairs.

"Huh? Why?" Lang Zhi looked completely bewildered and pointed at himself. "Just me?"

"Go on. Maybe after talking with Coach Ninomiya, you won't think so much." Kōshū snatched Lang Zhi's bat and wiped the sweat off it with the hem of his shirt.

"What are you talking about? Tell me already."

"Won't you find out when you go?" Kōshū ignored him after that, leaving Lang Zhi no choice but to walk off uneasily.

About a minute after Lang Zhi left, Kōshū stepped outside. Concealed by the darkness, he watched the nervous short boy stiffly walk down the second-floor corridor to the office door. He stood there for a full three seconds before finally knocking and going in.

That little runt. A faint smile touched Kōshū's lips.

"Whoo..." He turned around.

The field behind him slept in darkness. It was hard to imagine how lively it had been during the day, just as it was hard to imagine how noisy a sleeping baby could become once it woke.

I ended up talking with Coach Ninomiya for so long without realizing it.

"Kōshū, did you just come out?" It was Hayakawa Aki. From the direction he had come from, Kōshū could see light spilling out from the Bullpen.

"Coach Ninomiya told me about the arrangements for the next six months."

"Mm, it was about time. The one-on-one meetings."

"One-on-one meetings?" Kōshū pointed upstairs. "For more than forty people?"

"That's right. The coaches discuss each player's future plan in advance, then explain it to the players through one-on-one meetings. They also send it to the parents."

Kōshū's scalp tingled. That workload alone sounded enormous.

"Haha, that's why my family is planning to send my younger brother here too. But... it may have to wait until after I leave."

Hadn't Hayakawa said he and his younger brother were only two years apart? Kōshū faintly sensed Hayakawa's envy and comforted him, "Then you can still be together for two years. You'll be together in high school too, right? Brothers playing baseball together."

Hayakawa seemed to be thinking about something else. He softly said, "Maybe."

Outline progress: Today, I roughly worked out the outline for around ten chapters. I have to start writing matches soon. I'm doomed, I'm doomed—I still don't understand Pitching Strategy.

Later plans 1: First I'll write out the entire team's philosophy. After that, I may hit the accelerator and rapidly let Kōshū grow. Everyone is here for an Ace of Diamond fanfic, but I've written nine chapters without getting anywhere near it. I'm starting to feel like I'm going off-topic.

Later plans 2: Miyuki absolutely has to appear in the next chapter or the one after. He needs to lure Kōshū to Seido.