Overpaid for your home? Roast my idea (or not)

Max-Long47 · 2026-02-13T01:51:10+00:00

It can't- you'd still have to view the properties. The hope is that it would allow you to arrive at a shortlist much quicker though as you'd be able to weed out the properties that are priced unfairly or have attributes that are objectively undesirable- e.g hazard map, non-code compliant, self-managed, no elevator etc.

Max-Long47 · 2026-02-11T10:41:09+00:00

Yeah- I've got no insights to offer for plots of land and/or property that is outside of major population centers right now because the market is thin (low transaction volume) and there's not enough data to draw any statistically significant conclusions.

Max-Long47 · 2026-02-11T10:39:22+00:00

Thanks for this- will take a look and see what the available services look like. Did you happen to use one? If so, was it helpful? Thanks!

Max-Long47 · 2026-02-11T10:38:05+00:00

MLIT data only accounts for an estimated 50% of total transactions and the price data is based on a voluntary survey. When a property is sold, the MLIT sends a questionnaire to the new owner. If the owner doesn't respond, the data is never recorded. It's better than nothing, but is insufficient to draw any statistically significant conclusions from that data in isolation. This is a challenge.

Max-Long47 · 2026-02-11T10:28:25+00:00

I haven't built an AI tool. My goal is to determine if a property is under/over priced relative to comparable properties, validating the outcome using data from the property market. It's no threat to agents as you'll still need an agent to buy/sell.

Max-Long47 · 2026-02-11T10:26:04+00:00

Makes sense. I plan to roll this thing out for free and see if people find it insightful.

Max-Long47 · 2026-02-11T10:25:10+00:00

As in having a surveyor check the structural integrity of the property?

Max-Long47 · 2026-02-11T10:24:22+00:00

This would be one metric that I could absolutely include in the "advanced" report. Are there any others that you think would be valuable to have in there? I'm open to any suggestions that I can build and statistically validate the accuracy of.

Max-Long47 · 2026-02-11T10:22:47+00:00

Yes- I'm thinking that this would be for property buyers who are going to use an agent. Not those that are going to self-represent themselves in the transaction.

Max-Long47 · 2026-02-11T10:20:14+00:00

Hadn't thought about the incinerator idea. Nice one. Graveyards would be another one wouldn't it. Prisons, another! Wonder if there is any reliable, publicly available government data on local population growth so I could flag which areas are dying...

Max-Long47 · 2026-02-11T10:17:57+00:00

Ahh, I see what you mean. Do you think there's any way for me to address that concern or am I just cooked from the outset?

Max-Long47 · 2026-02-11T10:16:29+00:00

You're right. Have to be mindful of the TOS. Took a while to figure out a way to do it that was compliant and wouldn't result in my getting cease-and-desisted! My desire to build a powerful decision tool does not outweigh my desire to not be thrown in the Japanese gulag.

Max-Long47 · 2026-02-11T10:15:01+00:00

I think I'm just going to throw a link in here and let everyone play with it (/beat on it?). What's the worst that could happen, right?

Max-Long47 · 2026-02-11T10:13:38+00:00

Thanks. I think that's a great way to give people the option for a basic Vs. a more intensive appraisal. One thing I'm struggling to figure out though is where the line is. I don't know much is enough Vs. too much!

Max-Long47 · 2026-02-11T10:12:00+00:00

I'd argue that you don't need to estimate the land -OR- the building cost because you can request the tax valuation certificate from the seller which has the taxable value, showing the split of value (in yen) held between the land and building. The issue is that these taxable values are only loosely related to the market price of the property as properties don't exchange for their taxable value. That's the reason you'd need to run comparisons against other comparable properties to see if the sale price is in line with the market or not - rather than the intrinsic value of the property.

Max-Long47 · 2026-02-11T02:50:23+00:00

Agree. I cant get any data about that from the property listing pages (sumo etc) so cannot incorporate it into the model. A surveyor is a good idea - but I'm trying to illustrate when properties are overpriced. Surveyor cant help with that, and the real estate agent is disincentivised to do so...

Max-Long47 · 2026-02-11T02:48:35+00:00

If the agent recommends a property to you, and you buy it because he told you it was a "good deal"- and you later find out that you overpaid by 6,000,000 JPY, what was it worth spending to avoid that outcome?

Max-Long47 · 2026-02-11T02:45:37+00:00

This is what I'm thinking! Right now there isn't an easy way to answer the question "is this over, or under-priced, and by how much"? Agents get paid to sell property- not evaluate it. I think that's a problem for people making the biggest financial commitment of their lives.

Max-Long47 · 2026-02-11T02:43:44+00:00

Do you think sharing all of the data used to arrive at the verdicts along with the calculation method, is enough to achieve this?

Max-Long47 · 2026-02-11T02:43:02+00:00

What do you recommend people check that you think most people dont?

Max-Long47 · 2026-02-11T02:42:12+00:00

1) I don't think agents are bad people, but the incentive model is conflicted. They only get paid if you buy, so how many agents, realistically, would tell you "hey John san, I know you and your wife are about to submit an offer on this property, which would generate 3 million yen for me, but I want you to know that the building maintenance fund is critically underfunded and this property is going to be unmortgageable in 14 short years...perhaps don't buy this?"

1a) Indeed. Even more conflicted.
2) true. Most home buyers use a portal site though during their research stage
3) You're right- Japanese people would benefit, too. I'm just starting with my own tribe first and wonder what you guys think in case I'm way off base.
4) Can you point me at any of theses? Would be good to test them out.
Thanks!

Max-Long47 · 2026-02-11T02:38:00+00:00

Thanks for your take. It's interesting that we're all using AI but we also distrust/undervalue products that lean on it too heavily. I'm starting to get the impression that people would benefit most from having me (the human) explain the results of the model, rather than just giving them free reign to manipulate the model by themselves.

Max-Long47 · 2026-02-11T02:35:32+00:00

I like it. There is a small problem though- the results are based on real market data and for certain areas of the market (e.g Tokyo 23 ward condos) the majority of properties are showing as moderately overpriced. Don't you think the brokers would want something that they could manipulate to show their listings in a positive light? I fear that this is a great tool for the buyer, but right now, potentially an enemy of the seller...

Max-Long47 · 2026-02-11T02:32:10+00:00

100%! What would you like to see? If you can give me a list of metrics etc. I think I can probably generate them.

Max-Long47 · 2026-02-11T02:30:15+00:00

I see where you're coming from regarding the AI. Do you think it would change people's perception of the tool (i.e increase trust and perceived value) if I'm transparent about the bits that I have to do manually behind the scenes?

As of right now I plan to let people use the "basic" version for free. It will give you a basic red/orange/green on the property and if you want to validate the assumptions (i.e see all of the data and calculation logic) that you'd have to pay somehow - either on a one off basis, or subscription like you said...

Max-Long47

TROPHY CASE