Japan's Burglary Statistics — Trends by Building Type and Cost-Effective Countermeasures

TL;DR

• National Police Agency (NPA) data show detached houses absorb ~40% of residential burglaries — the highest-risk building type.
• ~55% of detached-house intrusions come through windows, and wall-climbing is the precursor route, so perimeter defence is the priority.
• Shinobi gaeshi are a one-off purchase (~150,000 yen) costing ~15,000 yen/year over a 10+ year life — far cheaper than monitored security at 3,000-6,000 yen/month.
• Burglars are rational and mostly opportunistic, so a visible physical barrier shifts their cost-benefit sum and pushes them towards an easier target.

When you plan security measures, data-driven decisions beat feelings and impressions. This article analyses the reality of burglary in Japan using the National Police Agency's crime statistics, and evaluates the cost-effectiveness of shinobi gaeshi against the numbers already on the record.

Where do intruders actually get into a home?

In detached houses, windows are the single biggest entry point at about 55% (NPA), followed by front doors (~18%), side/rear doors (~15%) and wall-climbing or roof routes (~12%). The catch: many window break-ins begin with climbing a wall or fence to reach a less-visible rear window, so window locks alone leave a gap.

Detached House Entry Points

Entry Point	Percentage
Windows	~55%
Front entrance (main door)	~18%
Other entrances (side/rear doors)	~15%
Other (wall climbing, via roof, etc.)	~12%

Window entry accounts for the majority, but the wall-climbing routes included in "other" deserve attention. Many burglars avoid the front entrance, instead climbing over walls or fences to reach the rear of the building and enter through less visible windows or side doors. In other words, even window intrusions often involve wall climbing as a preliminary step — the case for stopping the climb is set out in our wall-and-fence security spikes guide.

Apartment Entry Points

In apartments the picture shifts: the front door dominates at ~45%, with windows ~35% and balconies ~15%.

Entry Point	Percentage
Front entrance (main door)	~45%
Windows	~35%
Balconies	~15%
Other	~5%

In apartments, front door entry is most common, but balcony intrusions are frequent on lower floors. The 1st and 2nd floors have a risk profile similar to detached houses.

Are shinobi gaeshi actually cost-effective?

Yes. On the article's own figures, a one-off ~150,000 yen installation against ~750,000 yen average damage returns roughly 400% from preventing a single break-in. Spread over a 10+ year life that is ~15,000 yen a year — about 1,250 yen a month, well below monitored security at 3,000-6,000 yen a month, with no power or connectivity needed.

Damage Cost Analysis

Average damage from a residential burglary is estimated as follows:

Loss Type	Typical Amount
Cash losses	Average 200,000-500,000 yen
Jewellery and goods	Average 100,000-300,000 yen
Building damage (windows, doors, etc.)	Repair costs 100,000-300,000 yen
Psychological damage	Difficult to quantify (PTSD, relocation costs, etc.)
Total (monetary damage only)	Approximately 500,000-1,000,000 yen

Shinobi Gaeshi Installation Costs

Taking Ninja Deterrent products as an example:

• Product cost: From several thousand yen per metre
• Typical detached house perimeter: Approximately 30-50m
• Installation: DIY or professional installation
• Estimated total cost: Tens of thousands to several hundred thousand yen

ROI Calculation

Assuming shinobi gaeshi installation costs 150,000 yen and average burglary damage is 750,000 yen:

• ROI from preventing one burglary: (750,000 - 150,000) / 150,000 = 400%
• Shinobi gaeshi lifespan: 10+ years (stainless steel models are virtually maintenance-free)
• Annual cost: 150,000 / 10 years = 15,000 yen per year

That's approximately 1,250 yen per month — significantly less than typical home security service monthly fees (3,000-6,000 yen). The clearest way to see the value is to compare a one-off passive barrier with a recurring subscription:

	Shinobi gaeshi (passive barrier)	Monitored security service
Payment type	One-off purchase	Recurring subscription
Cost	~150,000 yen up front (~15,000 yen/year over 10+ years; ~1,250 yen/month)	3,000-6,000 yen/month
Power / connectivity	None required	Required
Failure risk	Virtually zero	Depends on power and comms
Protects an empty daytime home	Always, automatically	Only while powered and connected

Moreover, shinobi gaeshi require no power, no connectivity, and have virtually zero failure risk. For more on whether spikes genuinely stop a determined climber, see do anti-climb spikes work.

Frequently Asked Questions

Are detached houses really more at risk than apartments?

Yes. National Police Agency figures put detached houses at roughly 40% of residential burglary targets, far above any apartment category. Detached homes offer more potential entry routes and make it easier for an outsider to tell when the family is out. This is why perimeter measures matter most for houses rather than upper-floor flats.

Do shinobi gaeshi pay for themselves?

On the figures in this article, a 150,000 yen installation against an average 750,000 yen loss returns about 400% if it prevents a single break-in. Spread over a 10+ year service life, that is roughly 15,000 yen a year, or about 1,250 yen a month. Because they need no power, connectivity or subscription, the running cost after purchase is effectively zero.

If most break-ins are through windows, why focus on walls and fences?

Because the two are linked. About 55% of detached-house intrusions are via windows, but burglars frequently climb a wall or fence first to reach a hidden rear or side window out of public view. Stopping the climb at the boundary therefore also protects the windows behind it. Perimeter defence and window security work together, not in competition.

Are burglars deterred by visible spikes, or do they just find another way?

Most simply move on. Research finds more than 75% of burglars act opportunistically, and around 60% choose a different target when a deterrent is present (UNC Charlotte; Kuhns et al., 2012). Since a burglar weighs time and risk against reward, a visible barrier that threatens injury and delay usually fails the test before any attempt is made. From a household's point of view, that displacement is exactly the goal.

Are shinobi gaeshi cheaper than a monitored alarm?

Over time, yes. A monitored security service typically costs 3,000-6,000 yen every month indefinitely, whereas shinobi gaeshi are a one-off purchase that works out to roughly 1,250 yen a month across a decade-plus lifespan. The two are complementary rather than mutually exclusive, but the passive barrier carries no recurring fee, no power draw and no failure risk.

Do shinobi gaeshi need maintenance or power?

Very little. Stainless steel models are virtually maintenance-free and are designed to last 10+ years, needing only occasional inspection for rust, looseness or trapped debris. They use no electricity and no network connection, so they keep working during power cuts and while the house sits empty during the day. That always-on reliability is a large part of their cost-effectiveness.