How the rule works

The Civil Code deals with damage caused by a defect in the construction or maintenance of a structure on land. It is arranged in two tiers, and the second tier is where overseas owners should look closely.

First, the occupier of the structure is liable to the injured party. But where the occupier took the care necessary to prevent the damage, the owner must compensate instead.

Read that second sentence again. The occupier is given a way out. The owner is not. Ordinary liability in Japan turns on fault, but the owner's position here is not framed that way. Having been careful is not offered as a reason to be excused.

For a house standing empty, the owner and the occupier are usually the same person. There is nobody for the liability to pass to, and no point in the chain at which it stops with somebody else.

The same provision is applied to defects in the planting or support of trees. A tree is not a building, but it does not sit outside this.

A defect is not the same thing as age

This is the point most commonly misunderstood, so it is worth stating plainly. A defect here means the structure lacks the safety it ought ordinarily to have. It is a question about condition, not about date.

Three assumptions follow from that, and all three are wrong.

• It complied when it was built. Possibly, but a structure that has since deteriorated to the point of being unsafe can still be defective now.
• The previous owner built it. The owner is you. That is the whole of the test.
• It was the typhoon, or the earthquake. Where the structure would not have failed had it been sound, the natural event does not necessarily displace the liability.

Being able to say the structure was obviously old does not help. It tends to establish that the danger was there to be seen.

The block wall

Of everything on a Japanese residential site, the concrete block wall is the most likely to kill somebody, and Japanese neighbourhoods contain enormous numbers of old ones.

In 2018 an earthquake in northern Osaka brought down a block wall along a school route and a child died. The ministry issued a notice on inspecting existing walls, and inspections were carried out across the country. The reason the case mattered was not that the wall was unusual. It was that walls like it are everywhere.

The current standard for a reinforced concrete block wall is set out in the Building Standards Act enforcement order. In outline:

Two qualifications matter. Walls of 1.2 m or lower are outside the buttress and foundation requirements. And a wall verified as structurally safe by calculation under the prescribed method is treated separately from the list.

Now notice what you can actually see. Height and the presence of buttresses, and that is close to all. Whether there is reinforcement inside, at what spacing, and what the foundation does below ground are invisible from the street. A wall that looks solid tells you nothing about the two items most likely to decide whether it stands in an earthquake.

What an owner can check is the external evidence that something has already gone wrong:

• The wall leans. This is the clearest warning there is.
• Cracks, or joints that have opened.
• Rust staining bleeding through the face, which indicates corroding reinforcement.
• A wall over 1.2 m with no buttresses at all.
• Buttresses present, but spaced further apart than 3.4 m.
• Fencing added on top of an existing wall to gain height.
• A wall sitting directly on top of a retaining wall or stone facing.

On an older property, several of these together is an ordinary finding rather than an alarming one. Some municipalities and professional associations publish inspection sheets for owners.

What else is on the list

Block walls and gate pillars are the most dangerous. Beyond them, the recurring items are exterior render and tiles that can detach and fall, roofing and corrugated sheet that travels in high wind, retaining walls whose failure takes everything above them, trees and dead branches, and fixings that corrode until aerials, gutters and outdoor units come down.

Cheap property concentrates all of this. The wall is older, the retaining wall is further through its life, and the garden has been unattended for years. Buyers examine the building and skip the perimeter, which is precisely where the risk to other people sits. It belongs on the pre-purchase list alongside everything else you must verify yourself.

Trees, and a rule that changed

Trees carry a second problem on top of liability for a fall.

Japanese law used to require a landowner troubled by branches crossing the boundary to ask the tree's owner to cut them. Cutting them yourself was not permitted. That was amended, and in defined circumstances the neighbour may now cut the branches themselves. One of those circumstances is that the tree's owner was asked and did not act within a reasonable period.

An owner living abroad who cannot readily be reached is exactly the owner that provision was written for. It cuts both ways: you may need it when a neighbour's tree reaches your roof, and you may be the person on the other side of it.

There is a further consequence that is easy to miss. A neighbour who cannot reach you eventually contacts the local authority instead, and that contact becomes a record. Records of this kind accumulate, and they are what leads to a property being treated as poorly maintained, with the tax consequences that follow.

How large the numbers get

Damage to property is bounded by what it costs to repair or replace. Personal injury is not bounded in the same way.

A serious injury claim can include medical costs, lost earnings, lost future earning capacity where the injury is permanent, and compensation for the injury itself. A fatality is calculated against the deceased's age and income. Amounts vary enormously by case, but they can exceed what the property cost several times over. A house bought for the price of a car can generate a liability of an entirely different order.

Fire is a separate question. Japan has specific legislation limiting liability for fire that spreads to neighbouring buildings, and how it interacts with liability for structures is not straightforward. Collapse, falling material and wind-blown debris, however, fall squarely within the rule described here.

There are two defences, and only two

Do not let the hazard exist

This is the real answer. A leaning wall, cracked render, a dead tree, lifting roof sheets. These conditions are visible for months or years before anything falls, and somebody looking at the property during that window prevents the accident outright.

Inspection with dated records does two jobs at once. It stops the accident, and it produces evidence that the property was not neglected if an accident happens anyway. Photographs taken on a schedule are worth more than any assurance given afterwards.

Insure against the claim

Fire insurance policies in Japan can carry riders covering liability to third parties. Which rider is available to you depends on how the building is classified, and a house with nobody living in it is generally classified differently from a home. The classification changes what can be attached to the policy.

So the question is not whether the property is insured. It is whether a liability rider is attached, under the classification this particular building actually has. Those are different questions with different answers, and owners routinely assume the first covers the second.

Before you buy, and after

Listing photographs show the interior and the elevation. They do not show a wall out of plumb, a retaining wall beginning to bulge, a dead tree at the back of the plot, or roof sheets that have lifted at one corner. From completion, all of it is yours, including the consequences if it reaches somebody.

On low-priced property this matters more rather than less, for the reasons set out in what a cheap Japanese house actually costs. The perimeter is old wherever the price is low.