“It’s More Expensive Than the Market Price”: An “IT-Illiterate” Salaryman Who Used AI to Buy His Dream Home for 6.2 Million Yen Less Than Listed
Even for an average office worker who’s “not tech-savvy”…
AI (artificial intelligence) has become an indispensable part of our daily lives.Whether you’re seeking advice, planning a trip, or looking for a store, it instantly provides the best solution. In fact, some savvy individuals have even used AI tools like “ChatGPT” (hereinafter “Chappy”) and “Gemini” to negotiate a price reduction equivalent to their annual income when buying a home.
He published his experiences in the book *I Saved 6.2 Million Yen Buying a “Pre-Owned Home” in the Tokyo Metropolitan Area Using AI* (Tetsujin-sha) and even made a profit from it. Who exactly is Yuta Yokoyama (38)?
“I’m just an ordinary office worker with no specialized knowledge of real estate. I’m not good with IT either—I’m at the level where I barely managed to pass the IT Passport exam. I’m an ‘IT novice’ who leaves all my smartphone settings entirely up to my wife.
However, precisely because I’m not a real estate or IT expert, I turned to AI to ask about difficult technical terms and the industry’s opaque practices. By leveraging AI, I managed to negotiate a total savings of 6.2 million yen, but if anyone uses AI wisely, they should be able to buy a home at a lower price.” (Mr. Yokoyama; all comments in quotation marks are his)
Mr. Yokoyama lived with his wife and two children—a family of four—in a 40-year-old, 62-square-meter, 2-bedroom, 1-living-room wooden rental apartment in Kanagawa Prefecture with a monthly rent of 85,000 yen. The bath didn’t even have a reheating function, and he spent his days worrying that the neighbors might complain whenever his young children ran around.He considered buying a home, but since new condos in the Tokyo metropolitan area had become unaffordable for the average salaryman, he decided to look for a pre-owned home. That’s when he realized there seemed to be no such thing as a “fair price.”
“Even for similar properties in the same neighborhood, asking prices vary widely.The asking price is a ‘suggested retail price’ that reflects the seller’s wishes and the real estate agency’s circumstances—it’s different from the actual sale price. The real estate industry is reluctant to disclose actual sale prices, so it’s a world without fixed prices. Without specialized knowledge, you can’t compete—so it’s safe to assume you’ll be taken advantage of.”
When viewing a property, your heart races at the sight of a sun-drenched living room or a spacious balcony. Without missing a beat, a seasoned salesperson urges you to buy, saying things like, “You won’t find this price in this area again,” “There are other buyers considering this property,” or “If you decide to buy today, I’ll negotiate with the seller to knock off the remaining 800,000 yen.”
In fact, Mr. Yokoyama admits, “I was tempted to jump at the salesperson’s offer.” In an industry full of arbitrary pricing, he says he “took a moment to calm down” to avoid being fooled by the salesperson’s clever pitch.
“I bought some time by saying, ‘I’ll give you an answer by tomorrow,’ and then consulted with AI at home. Chappy brought me back to my senses, warning, ‘Be careful. A sudden discount offer is a sign of desperation.’
Gemini researched the market rates for similar properties in the neighborhood and told me, ‘This is a reasonable price.’Furthermore, it clearly pointed out future risks, asking, ‘In X years, major renovations will coincide with your child’s entrance exams—do you have sufficient funds?’ Humans are swayed by emotions, but since AI has no emotions, it makes logical observations, and it has saved me time and again since then.”
Simply by having him read through documents like the Important Matters Explanation Statement,
Although Mr. Yokoyama was “technologically challenged,” he had secretly enjoyed using AI capable of generating highly realistic images for adult purposes, so he was aware of the rapid advancements in AI technology. This was a major purchase—the kind you make only once or twice in a lifetime. There was no room for error.
However, there were so many things a layperson wouldn’t understand. Even when looking at a pre-owned home, to what extent are cracks in the walls acceptable? Do the plumbing and bathroom areas need repairs?He had no idea how much renovation would be required, nor what a fair price for the work would be. Salespeople never reveal their true thoughts, but by harnessing AI, the optimal solution is calculated in the blink of an eye using each AI’s specialized capabilities.
Mr. Yokoyama uses the paid versions of Chappy and Gemini, each costing $20 per month (about 3,200 yen).In addition, he uses Anthropic’s “Claude” for $30 per month (about 4,800 yen) and the free version of the Chinese AI agent “Manus.” Using the “Four AI Titans” as both his offensive and defensive weapons, he decided to face off against the seasoned contractors.
As a test, he fed the AI documents rife with technical jargon—such as the Important Matters Explanation, building approval certificates, and home inspection reports—and it began pointing out one thing after another: defects he hadn’t noticed and estimated repair costs.
“While stains on walls caused by roof leaks can be seen with the naked eye, it’s difficult for a layperson to assess the condition of the roof or exterior walls. Hiring a professional costs money and takes time. But with AI, simply feeding it the property’s full disclosure statement allows it to logically infer the condition of the roof and exterior walls—as well as the cost of repairs—based on the building’s age and the type of roofing material.
If you feed the data into ‘Python’—a programming language widely used for data analysis—it can even predict future changes in sunlight exposure, forecast increases in long-term interest rates, and estimate loan payments several years in advance. It can also expose the true intentions behind a salesperson’s pitch and continuously provide the most relevant counterarguments.
Furthermore, when I fed it a renovation estimate, it pointed out one issue after another, saying, “This item may be priced higher than the market rate.” In my experience, in an industry that views customers who don’t know the market rate as easy marks, they’ll shamelessly overcharge you. However, if you know the market data, you can prevent this. It was AI that gave me that weapon.”
Can Be Used Even in Rental Properties
Each of the “Four AI Emperors” has its own unique personality. Mr. Yokoyama says he assigns roles based on those individual traits.
“Chappy excels at generating and organizing ideas, and is also skilled at drafting documents. It’s well-suited for drafting emails for price negotiation and advising on how to respond to salespeople. Gemini works well with Google Search; it points out the current status and changes in the surrounding area, allowing us to complete preliminary research without having to visit the site.
Claude excels at reading and understanding long texts and crafting polished prose, making it well-suited for reviewing specialized and lengthy documents. Manas is self-reliant; when given instructions, it plans the workflow and carries out the tasks, so I can entrust it with collecting and organizing property information.
“Rather than relying on just one AI, when making major decisions, I posed the same question to several AIs to gather additional information as second and third opinions.”
By making full use of AI, Mr. Yokoyama managed to negotiate a 3 million yen discount on the property price and reduce renovation costs by 2.6 million yen. Furthermore, he cut the notary’s fee for real estate registration by 200,000 yen, fire insurance by 320,000 yen, and moving expenses by 80,000 yen—saving a total of 6.2 million yen.
“My children run around the spacious interior, my wife soaks in our state-of-the-art bathtub with a reheating function, and we’re thoroughly enjoying life in our single-family home. Our monthly payments are roughly the same as our previous rent, and once we’re done paying, the house becomes an asset. I want to continue using AI to enrich our lives going forward.For example, by having Gemini analyze receipts from nearby supermarkets—to determine which stores offer the best prices and when sales are held—we can even overcome inflation.”
Finally, when I asked if renters could also use AI to negotiate discounts when moving or renewing their lease, Mr. Yokoyama nodded vigorously and replied:
“With renting, everything from move-in to move-out is a negotiation, so ‘AI-driven discounts’ really come into play. If you provide data on local rental market rates and the property’s vacancy period, it becomes leverage for negotiating lower rent or renewal fees.
Even now, there are still quite a few companies that overcharge for restoration costs when tenants move out. Simply feed the AI your move-out invoices and estimates, and instruct it to ‘determine, item by item, whether the tenant’s share of the costs is reasonable based on the Ministry of Land, Infrastructure, Transport and Tourism’s guidelines for restoring the property to its original condition.’It will check whether items that should actually be the landlord’s responsibility—such as normal wear and tear or natural aging—have been included in the charges. If you send a well-reasoned inquiry, the amount charged may be revised, potentially saving you anywhere from tens of thousands to hundreds of thousands of yen.”
“Ask-and-you’ll-get” pricing is rampant out there. Inflation continues as well. To avoid getting ripped off, why not start tomorrow by asking, “Hey, Chappy”?
Reporting and Text： Daisuke Iwasaki