ISO 27001 Incident Response Plan for Japan Operations

Part of our guide to Japan’s cybersecurity landscape. For the regulatory map behind it, see Japan’s Cybersecurity Laws & Guidelines.

Most foreign teams building an incident response plan for Japan operations start from one of two places: an ISO 27001 auditor’s checklist, or a NIST-style playbook they already run everywhere else. Both are correct starting points, and neither one is complete on its own once ISMAP or a Japanese sector regulator enters the picture.

As an information security practitioner working with foreign companies operating in Japan, I want to walk through what ISO 27001 actually requires for incident response, how that maps cleanly onto a NIST-style plan most security teams already understand, and where Japan adds requirements the ISO baseline doesn’t cover.

What ISO 27001 actually requires for incident response (Annex A 5.24–5.28)

ISO/IEC 27001:2022 consolidated incident-related controls into a five-control sequence in Annex A, replacing the more scattered 2013 structure. Read together, they describe a full lifecycle rather than five independent requirements:

• A.5.24 — Information security incident management planning and preparation. A documented incident management policy and procedure must exist before an incident, covering roles, responsibilities, and escalation paths. This is the control auditors check first, because everything downstream depends on it existing in writing.
• A.5.25 — Assessment and decision on information security events. Not every event is an incident. This control requires a defined process — and criteria — for classifying events by severity and deciding which ones get escalated.
• A.5.26 — Response to information security incidents. The active response itself: containment, eradication, and recovery, executed according to the documented procedure rather than improvised in the moment.
• A.5.27 — Learning from information security incidents. A required post-incident review that feeds lessons learned back into the plan, controls, and training — this is what makes the cycle continuous rather than a one-time document.
• A.5.28 — Collection of evidence. Procedures for identifying, collecting, and preserving evidence in a way that satisfies internal and external (including legal) requirements — chain of custody, not just log retention.

The control that trips up the most first-time auditees is A.5.24 alone: a documented policy is a mandatory baseline, and “we handle incidents case by case” is a nonconformity regardless of how well the team actually performs during a real incident.

Mapping ISO 27001 clauses to a NIST-style incident response plan

If your organization already runs an incident response program built around NIST SP 800-61, you don’t need to build a second, ISO-flavored plan from scratch. NIST SP 800-61 defines a four-phase lifecycle — Preparation; Detection and Analysis; Containment, Eradication, and Recovery; and Post-Incident Activity — and it maps onto the five ISO 27001 controls almost one to one:

The practical takeaway: keep the NIST lifecycle as your operational muscle memory, but add (1) a written classification rubric to satisfy A.5.25 and (2) a standalone evidence-handling procedure to satisfy A.5.28. Those are the two places a NIST-native plan most commonly falls short of ISO 27001, not the response process itself.

Where Japan’s ISMAP and sector guidelines add requirements beyond ISO 27001

ISO 27001 certification — even done well, even mapped cleanly to NIST — is not the finish line for organizations selling cloud services to Japan’s public sector or operating in a regulated sector in Japan.

ISMAP. Japan’s Information System Security Management and Assessment Program is built on ISO/IEC 27001 but layers on program-specific operational controls, including defined reporting thresholds and timelines to the ISMAP management body for incidents affecting government information or the registered service scope. An ISO 27001 certificate demonstrates the underlying ISMS is sound; it does not by itself satisfy ISMAP’s incident reporting obligations, which are assessed separately as part of ISMAP registration (see our ISMAP certification guide for how the registration process itself works). Treat ISMAP’s reporting timeline as an addition bolted onto your A.5.25/A.5.26 procedures, not a replacement for them.

Sector guidelines. Regulated sectors in Japan — financial services in particular — commonly layer sector-specific incident notification expectations on top of the general ISO/NIST baseline, with their own thresholds for what must be reported and how quickly. These sit alongside, not instead of, the Act on the Protection of Personal Information (APPI)‘s breach reporting duty to the Personal Information Protection Commission (PPC), which is a separate legal track from both ISO 27001 and any sector-specific guideline.

Coordination. JPCERT/CC functions as Japan’s incident coordination point and works with network operators, security vendors, and other CSIRTs to help resolve incidents with a Japan nexus (JPCERT/CC). Neither ISO 27001 nor NIST SP 800-61 names this relationship explicitly, so it needs to be added to your plan’s escalation path if any part of your operation touches Japan.

The pattern across all three: Japan doesn’t replace the ISO 27001 / NIST structure, it adds parallel reporting tracks — to the ISMAP management body, to a sector regulator, and to the PPC — that your plan needs to name explicitly rather than assume are covered by “notify the regulator.”

Evidence auditors expect to see at your next surveillance audit

A written plan satisfies A.5.24 on paper. Surveillance audits check whether it was actually used. Auditors typically sample:

• A dated incident log, even a thin one — an empty log across a full audit period, with no simulated or tabletop exercise to point to instead, is a common nonconformity finding.
• Evidence the classification criteria were applied, not just that a rubric exists in the plan document (A.5.25).
• Containment and remediation records tied to a specific logged incident (A.5.26).
• A completed post-incident review, with lessons recorded and — this is the part teams skip — evidence those lessons actually changed the plan, a control, or training (A.5.27).
• Evidence handling with a documented chain of custody, not just “we kept the logs” (A.5.28).

If your organization hasn’t had a real incident since the last audit, a documented tabletop exercise covering the same evidence points satisfies the auditor just as well — and is worth scheduling deliberately rather than hoping a real incident happens to validate the plan before the next surveillance visit.

Building one plan that satisfies both ISO 27001 and Japan regulators

Bringing this together, a single incident response plan for Japan operations — rather than a separate ISO-compliance document and a separate “Japan procedures” addendum — should contain:

1. A documented policy and named roles (A.5.24), reviewed and re-issued on a defined cycle.
2. A severity classification rubric (A.5.25) that produces a consistent escalation decision, not analyst judgment case by case.
3. A NIST-style response procedure (A.5.26) — containment, eradication, recovery — that your team already knows how to execute.
4. A parallel notification fan-out, run concurrently rather than sequentially: PPC and any sector regulator under APPI and sector-specific rules, the ISMAP management body where the registered service scope is affected, and JPCERT/CC where the incident has broader implications for Japanese network operators.
5. A standalone evidence-handling procedure (A.5.28) with defined chain of custody.
6. A mandatory post-incident review (A.5.27) that fixes gaps in the plan itself — not just in the technical controls that failed.

None of this requires abandoning a NIST-native program or building Japan-specific tooling. It requires naming, in one document, the reporting tracks Japan adds on top of the ISO/NIST baseline — and being able to show an auditor evidence the plan was actually exercised, not just written.

Sources: ISMS.online — ISO 27001:2022 Annex A 5.24 Explained · JPCERT/CC — About · 38North Security — What is ISMAP?