We let a probation period lapse and could not undo it — the 6 checks I now run before any Tokyo engineer starts

The engineer was not a bad hire. That is what made it awkward. Three months in, the picture was mixed in the way that genuinely mixed cases are: strong on delivery, difficult in code review, and unwilling to work inside decisions the team had already made. We were discussing what to do about it in the second week of month four, when someone checked the offer letter and pointed out that the probation period had ended eleven days earlier.

Nothing dramatic followed. But the wider margin of discretion probation had given us was gone, and the conversation shifted from assessment to performance management — a much longer road. That episode is why the six checks below exist, and why the sixth one is the one I would keep if I could only keep one.

Check 1 — Understand what probation actually changes

Start by correcting the assumption most foreign-managed companies arrive with. A probation period — shiyo kikan — does not create at-will employment for its duration. Japanese employment practice treats dismissal as requiring objectively reasonable grounds that are socially acceptable, and that framing does not switch off during probation.

What probation does give you is a somewhat wider margin: grounds that would be insufficient for a confirmed employee may be sufficient during an assessment period explicitly agreed in advance. The margin is real and worth having. It is also much narrower than the phrase “probation” suggests to anyone whose instincts were formed in the United States. A decision that rests on general dissatisfaction, without documented and communicated shortfalls, is exposed regardless of what the offer letter says.

Check 2 — Put the clause in the work rules and the offer

Probation is a contractual arrangement, which means it exists only if it was agreed before the person started. Two places matter. The work rules should state that a probation period applies, its standard length, the possibility of extension and the grounds on which confirmation may be refused. The individual offer should then state the specific dates for this person.

Companies below the threshold that triggers the obligation to file work rules sometimes conclude they can skip the document entirely. That is a mistake for exactly this reason: without work rules, the framework your probation decision would rest on does not exist in writing. The related problem of getting invention and IP clauses into place before signature follows the same logic — our colleagues have written about that in the piece on invention clauses under Article 35, where a clause added later cannot reach backwards either.

Check 3 — Define the evaluation criteria before day one

This is the check that does the most work, and it costs an hour. Before the person starts, write down what you will assess and how. For an engineering role that usually means four or five items: technical delivery against agreed scope, code quality as judged in review, collaboration and responsiveness to feedback, reliability on commitments, and ramp-up speed relative to the level hired at.

Then share the list with the person in week one. This feels excessive to teams used to informal probation, and it is exactly what makes the difference. If a difficult conversation happens at month three, you want it to reference criteria the person received in week one, alongside feedback they were given at the time. Criteria produced after the problem appeared read as justification rather than assessment — to the individual, and to anyone reviewing the decision later.

Check 4 — Know the 14-day rule and the notice obligation

There is a narrow window at the very start of employment — the first 14 days — in which the advance-notice requirement that normally accompanies dismissal does not apply in the same way. After that, the standard obligation applies: broadly, 30 days of advance notice, or payment in lieu of that notice.

For engineering hires this window is close to useless in practice, and it is important to say so plainly rather than to plan around it. Fourteen days is not enough to assess whether someone can build and maintain software in your environment; most people are still setting up their machine and reading the codebase. So assume from the outset that any probation decision will be made under the full notice obligation, and budget for it. The teams that get caught out are the ones who half-remember “there is a two-week rule” and discover its scope on the day they need it.

Check 5 — Treat extension as the exception it is

Extending probation is possible where the work rules provide for it and there is a legitimate reason — a long absence during the period, a significant change in role, or a genuinely borderline assessment where more observation is fair to both sides. It is not a way to defer an uncomfortable decision.

If you extend, do three things. State a specific reason in writing rather than a generic formula. Set a defined end date rather than an open-ended continuation. And be explicit about what has to change, in terms concrete enough that the person can act on them. An extension that communicates only “we need more time” leaves someone in an uncertain status without the information they would need to improve — which is both unfair and, if the matter is ever examined, unhelpful to you.

Check 6 — Decide before the period lapses

This is the one that cost us. When a probation period ends without a decision, the employee is confirmed, and the wider margin disappears. There is no retroactive mechanism, no grace period, and no way to reopen the assessment because you were busy.

The fix is embarrassingly simple, which is why it is worth stating: put the probation end date in a shared calendar the moment the offer is signed, with a reminder two weeks before, assigned to a named person rather than to a team. Two weeks is deliberate — it leaves room for a conversation, a documented feedback session, and a decision that is not made in a rush on the final afternoon.

In almost every case I have seen since, the assessment itself was not the hard part. Managers usually know by month two. What fails is the administrative link between knowing and acting, and that link is a calendar entry with an owner.

What good looks like

A probation period that works is unremarkable from the inside. The criteria were shared in week one. There were two or three short documented conversations along the way, none of which surprised anyone. Two weeks before the end, a reminder fired, a manager wrote three paragraphs, and the person was confirmed — or, occasionally, was not, and understood exactly why because nothing in the conversation was new to them.

The version that goes wrong is equally recognisable: no written criteria, no interim feedback, a decision discussed informally for weeks, and a date discovered after it passed. The difference between the two is not legal sophistication. It is about an hour of preparation before day one and one calendar entry. If you are building a team across several countries, it is worth noting that this administrative discipline transfers even where the law does not — colleagues at HireDeveloper.sg and HireDeveloper.ae describe the same failure mode in Singapore and the UAE, with different rules and identical consequences.

Frequently asked questions

Can we dismiss freely during probation in Japan?

No. Probation gives a somewhat wider margin of discretion, not at-will employment. A termination during probation still needs objectively reasonable grounds that are socially acceptable, and a decision resting on vague dissatisfaction rather than documented, communicated shortfalls is exposed.

What is the 14-day rule?

Within the first 14 days of employment the advance-notice requirement does not apply in the same way; afterwards the standard obligation applies — broadly 30 days notice or payment in lieu. For engineering hires the window is too short to assess capability, so plan on the full obligation.

How long should a probation period be?

Three to six months is the common range, with three months typical for engineering roles. Longer is not automatically better: an unusually long probation invites the argument that it keeps someone in a precarious status rather than assessing them.

What happens if we miss the end of the probation period?

The employee is confirmed by default and the wider margin is gone. There is no retroactive fix. This is why a calendar entry with a reminder two weeks earlier, owned by a named person, is the highest-value control in the whole process.

This article is general information for employers, not legal advice. Probation practice depends on your work rules, the individual contract and the facts of each case — take Japan-qualified advice before acting on a specific situation.