Under prime contractors undertaking plant maintenance, there are various specialized companies, such as those dealing with electricity, generators, boilers, and turbines. Shimizu Koki undertook valve maintenance work as a subcontractor for a company specializing in valves. They primarily performed valve maintenance for thermal power plants.
Although simply called “valves,” they range from small ones like water faucets to large ones that a person can enter.

“At a single thermal power plant, there are 300 to 400 valves to inspect.”
Furthermore, there are various types of valves, such as gate valves and butterfly valves.
During inspection, each valve is disassembled to remove dirt. In areas prone to cracks, a color check is performed, and if the condition is poor, it is reported to the customer.

During maintenance, lapping is sometimes performed to eliminate gaps between the valve body and valve seat. If the grinding angle or applied force is incorrect, even if scratches are removed, the parts may not fit perfectly.
“Since the abrasive particles are thicker on the outside than on the inside, there's a certain intuitive aspect to it.”
Nevertheless, Yu says it's not that difficult if you have the right tools.

In general factories, it has become more common to replace valves rather than repair them when they malfunction or move poorly.
However, large valves used in thermal power plants cannot be easily replaced. Furthermore, disassembly for maintenance requires extensive experience and skill.
To remove valves weighing 500kg to 1t, a chain block must be attached and a wire hooked. However, the site does not always provide a dedicated space for this.

It starts with considering where to attach the chain block for safe lifting.
There were also cases where a structure required lifting by about 800mm to be removed, but only 600mm of clearance was available.
Furthermore, the placement of lifted parts must be carefully considered. In areas with electrical wiring, the orientation sometimes had to be adjusted to avoid disconnection.
Thus, observing the site and devising the optimal method within that context is not something anyone can do just by “having tools.”

Shimizu Koki has gradually increased its operations beyond valve maintenance, and in recent years, the proportion of maintenance for various factory machinery and equipment such as pumps, fans, and blowers has grown.
This is largely due to Yu's knowledge gained as a supervisor's assistant for large fans at his previous company. Prime contractors who knew of Yu's experience sometimes requested work other than valves. In this way, by gradually gaining experience in various types of maintenance, they have expanded their scope of work.

A characteristic of Shimizu Koki is their willingness to attempt maintenance even on machines they've never seen before.
“There are various shapes, but anything that rotates always has a drive unit and mechanical transmission. Rotating machines have various types of bearings, and beyond that, there are blades or screws for performing work. I have an unfounded confidence that if I understand the basic structure, I can handle even machines I'm seeing for the first time.”

Nevertheless, to perform work more accurately, Yu asks customers if they have drawings or disassembly manuals.
Often, such documents are not available, but Shimizu Koki utilizes its knowledge and experience to successfully complete such requests, achieving results. They have earned deep trust from customers, who think, “Shimizu Koki will surely find a way.”
This is likely greatly influenced by their experience in valve maintenance, where various judgments must be made on-site.
Maintenance work might well be called being a doctor for machines.

The fear in performing maintenance is “time.”
“If we are asked to complete maintenance within a certain period, we must finish it within that time. If the schedule slips, it will halt the factory's production.”
Anything can happen on a maintenance site. Having to complete it within the time limit is a huge pressure.
“We are often called when customers are in trouble, so there's also the joy of being thanked for completing the work precisely within the set period.”
The magnitude of pressure and sense of accomplishment may be proportional.

While aiming to finish the work within the time limit, they sometimes call a halt. For example, when faced with a situation where forcing it might break a bolt.
“I tell my staff to always report and consult if they find anything suspicious.”
It's not shameful to assess the machine's condition and say it's impossible. It's a judgment that can only be made by thoroughly understanding the machine's condition.
“Even if there's a possibility that the work cannot be completed within the scheduled time, it takes courage to stop it temporarily.”
It is precisely because of the trust in Shimizu Koki's technical expertise that customers can accept such reports.

Maintenance involves disassembling a machine once and then reassembling it. While it sounds simple in a single phrase, some companies take an enormous amount of time, and others cannot properly reassemble it.
“Even if it looks reassembled at first glance, there are cases where malfunctions occur during use.”

For example, differences in skill and knowledge become apparent in seemingly invisible parts, such as the order and torque for tightening bolts, or the required gap width. While these may seem like small differences, they affect the machine's lifespan.
Shimizu Koki keeps records of the original condition, using sketches, photos, and notes.
Such meticulous and sincere work leads to accurate operations and customer trust.

Yu is concerned about the labor costs for maintenance work.
“We don't manufacture and sell products. Therefore, we sometimes feel that the labor costs are not appropriate.”
For example, prime contractors need to supervise the work of subcontractors. While some subcontractors require constant, detailed supervision, others can be largely entrusted with minimal oversight. However, even in the latter case, the labor cost is not increased for that added value.

When Yu was young, he once completed a project scheduled for about a week in three days through various innovations. At that time, the supervisor reportedly said, “I wish you would take your time and spend a week on it.”
The ability to shorten a project that would originally take a week is due to their technical skill and knowledge. However, he was told that if a week's work wasn't done over a week, they couldn't bill the customer for that amount.

“Even if we finish early, we don't get a 'thank you.' In reality, since the factory can resume operation sooner, the labor cost should be increased.”
In such a situation, the number of people who want to work in this industry will not increase, and on-site motivation will not improve.
“Ultimately, what we sell is not products, but people. That's why we strive to earn trust in our people.”

They build trust with customers as someone they can “easily call for consultation” when they have a problem, or who “will find a way even with difficult issues.”
This allows Shimizu Koki to be chosen not just based on price, but on their technical expertise and human capability.

Shimizu Koki generally does not refuse requests, even for unfamiliar machines or difficult projects.
“It's easy to refuse. But I just think it's cool to be able to do difficult things.”
However, they do not believe that Shimizu Koki alone can solve everything.They aim to increase their network of partner companies of similar size to Shimizu Koki and create an environment where they can mutually assist each other.

Each company has different strengths. By combining their respective strengths, they will be able to achieve even higher performance.
By gathering companies with specialized fields, including Shimizu Koki, new possibilities may emerge.