Buying Operations Software in Japan: A Straight Guide
Ask where rounding happens, and ask to see the tax for one rate on a two-rate invoice. Our own answers are on this page, and the first one is a number that cannot be paid.
Most software evaluations in Japan spend their time on the wrong half of the invoice. The qualified invoice system has been live since October 2023, every vendor will tell you they support it, and the sentence is close enough to true that it does not distinguish anybody. What distinguishes them is arithmetic — and arithmetic is checkable in about two minutes without a demonstration, a proposal or a call.
Below are the questions worth asking, with our own answers published beside each one. We come out of several of these badly. That is the point: a vendor page that asks you to interrogate everybody else and never answers first has told you nothing about itself.
1. Raise an invoice with prices that are not multiples of ten
Three lines, standard rate, ordinary prices. Then look at the consumption tax figure and ask a simple question: is that an amount of money? The yen has no subunit, so any fractional part is not a rounding preference — it is a denomination that does not exist.
Our answer
Lines of ¥1,980, ¥333 × 3 and ¥1,255 at 10% produce a tax of ¥423.4 and a total of ¥4,657.4. Our invoice arithmetic rounds to two decimal places as a hardcoded literal and does not read the currency's own precision, which we hold correctly as reference data and publish on our market pages. The fix is on our list with a price on it.
2. Put an 8% line and a 10% line on the same document
Then ask to see the consumption tax for each rate. A qualified invoice must show the tax categorized by tax rate, and because the 8% band covers food and some subscriptions, a mixed invoice is an ordinary document rather than an exotic one.
This is the question most likely to be answered with a total and a change of subject. A system that can only produce one tax figure is not producing a compliant document, however correct that figure is.
Our answer
We cannot produce it. The rate is stored on each invoice line and the tax is stored on the invoice header as a single figure, so the per-rate subtotal in between does not exist. It is the same piece of work as the rounding fix, which is why we would build the two together rather than in sequence.
3. Ask where rounding happens — and check the answer against an invoice
There are three possible answers and they produce different numbers on identical data. Rounding once per line. Rounding once per document. Rounding once per rate band, per document. Japan's rule is the third, with the issuer choosing whether to round up, round down or use ordinary 4-versus-5 rounding.
Ask which one, then verify it on a document rather than in a specification. This is a question with a right answer in your market, not a preference.
Our answer
Once per document, to two decimal places. That is neither the number of places the yen has nor the rule Japan applies, and it cannot become that rule until the per-rate subtotal from question 2 exists.
4. Where do you record a supplier's registration number?
Your entitlement to credit the tax on a purchase depends on the invoice you keep being a qualified one, issued under a registration number. Ask to see the field. Then ask the follow-up that matters more: does the system claim to verify that number against the published register?
A vendor answering yes to the second question is offering you a dependency, not a feature. Your credit position would then rest on their copy of somebody else's data being current. The better arrangement is that the system holds the number you recorded and the date you checked it, and the checking stays with you.
Our answer
There is no field. Not on suppliers, not on customers, not on the organization itself — an absent column rather than a weak screen. Adding it is straightforward work we would commission. Verifying it against the register is something we would decline on purpose, for the reason above.
5. Enter a holiday that falls on the second Monday of a month
Then look at what the system thinks that holiday is twelve months later. Four of Japan's sixteen national holidays are fixed to the nth Monday of a month, and two more are announced annually rather than derived. A recurrence that repeats a date rather than a rule is correct in year one and drifts by a weekday every year after.
Our answer
Our recurring holidays repeat on the same month and day, so all four drift and the two equinox holidays cannot be expressed as a rule at all. Until an nth-weekday recurrence is built, the right answer for a Japanese organization is to enter those six as dated one-offs each year. We wrote this up separately because it reaches leave and availability, not just a calendar.
Two questions to take to your adviser rather than to a vendor
The transitional relief available on purchases from suppliers who are not registered issuers is real, it is dated, and it changes what a purchase is worth to you. It is a tax question with a schedule attached, and no software choice improves the answer. Ask your adviser, then ask the vendor whether the system can record what the adviser tells you.
The same goes for whether registering is right for your own business at all, if you are small enough for it to be a genuine choice. That is a commercial and tax decision about your customers, and a software evaluation is the wrong room to make it in.
What this list is actually for
Every question above can be answered from a trial account in under fifteen minutes, by you, without anybody's help. That is deliberate. The purpose of a buyer's guide is not to give you a script for a meeting — it is to move the decision out of the meeting entirely, to a place where the software answers instead of the salesperson.
And if you run those five tests on us and conclude that our arithmetic is not ready for your next filing period, that is a legitimate conclusion and we would rather you reached it now. The findings on this page are ours, they are published with the figures, and they are not conditional on anybody buying anything.
