Methodology

Scope

We primarily cover AI-oriented and hyperscale data centers in Japan. Listings are not limited to facilities that are exclusively AI-only; large colocation and hyperscale campuses used for AI/cloud compute are included. Individual pages note AI/cloud positioning when published by operators.

Evidence Level

Each facility is classified by the nature of its supporting sources. E0 (unverified) is never published.

• E0 — Unverified
• E1 — Media / secondary source
• E2 — Multiple independent sources
• E3 — Official company or government statement
• E4 — Primary permit / minutes / filing text
• E5 — Primary text + on-site verification

Location precision

When the exact site is not confirmed, map pins use the municipality centroid and we state that clearly. Approximate positions are never presented as exact facility locations.

• Exact location
• Block-level — Approximate location
• District-level — Approximate location
• Municipality centroid — This pin is the municipality representative point, not the exact facility location
• Location unverified — Location not verified (hidden on map)

Power capacity types

Power capacity may mean IT load, utility supply capacity, facility total, campus total (all buildings), or planned maximum including future phases. We always attach the type and do not aggregate or compare figures across different types as if they were the same measure.

Status and history

Status changes are always recorded as sourced, append-only events. History is not rewritten; mistakes are addressed with correction events. Do not confuse timeline event type "construction start" with facility status "under construction" — they are separate fields.

Corrections

Listings are not findings of illegality or impropriety. Operators and stakeholders may request corrections from each facility page.