Japanese Auction Grades, Explained: What USS's Numbers and Letters Actually Mean

The one-line version

A Japanese auction sheet carries at least three distinct pieces of information, and treating them as one number is the single most common beginner mistake: an overall exterior grade (a number from roughly 1 to 6, or S, plus R/RA for repair history), a separate interior grade (a letter, A through D or E), and a diagram of the car's own bodywork marking every scratch, dent and repainted panel with its own code. Read all three before you read a price.

Where the system comes from

Japan's used-car auctions are run by several competing operators — USS (the largest, with roughly 19 venues nationwide and a network dating to 1980 as Aichi Automobile General Services, officially renamed USS Co., Ltd. in 1995), plus TAA, JU, CAA and Aucnet (AIS) among others. Each operator employs its own inspectors, but the grading criteria all trace back to the same source: standards set by the Japan Automobile Appraisal Institute (JAAI). That shared root is why the symbols look broadly similar across venues — and why the grades still aren't perfectly interchangeable between them (more on that below).

The exterior number grade

The headline number describes overall condition, age and honest wear — not just cosmetics:

• S / 6 — Effectively new: under about a year old, minimal mileage, no meaningful wear. Vanishingly rare on anything old enough to import.
• 5 — Excellent, very light wear. Also rare once a car is past roughly a decade old.
• 4.5 — Very good, minor imperfections. The grade most buyers hope for on a 15-20-year-old JDM car, though genuinely uncommon at that age.
• 4 — Above average, honest age-appropriate wear, usually with some maintenance history behind it.
• 3.5 — The single most common grade for cars in the age band this site cares about: multiple small defects, a wide range of real-world condition hiding behind one number.
• 3 — Heavier cosmetic wear, more noticeable scratches/dents, sometimes early corrosion.
• 2 / 1 — Poor condition, significant corrosion or damage; usually project cars, not turnkey imports.
• R / RA — Recorded repair history (修復歴) on one of the car's core frame members. This is tracked separately from the number grade and isn't automatically a red flag: a widebody kit and a repaired minor collision can both trigger it. Ask what was actually repaired; don't just react to the letter.

The interior letter grade

Interior condition rides on its own A-E scale, independent of the exterior number: A (like new), B (light wear, minor marks — the most common grade on a well-kept car), C (visible staining, burns or wear needing cleaning), D (torn, heavily worn), and at some auction houses E (needs substantial restoration). A car can carry a strong exterior grade and a weak interior one, or vice versa — a summary that quotes only one number is quoting half the sheet.

The diagram: reading the map, not just the score

Below the two grades, every sheet includes a top-view diagram of the car marked with letter codes at each flaw's location — this is where the real detail lives. Common codes: A (scratch), U (dent, no paint damage), B (dent with paint damage), W (repainted panel — cosmetic, not necessarily structural), S/C (rust/corrosion), P (paint damage — chips, blistering), G (stone-chipped glass), X (damage flagged for replacement — some sheets use XX for a panel already replaced). A car can carry a perfectly respectable 4 or 4.5 grade and still show a repainted door or a corroded sill on the diagram — the number is an average; the diagram is the specifics.

USS vs TAA vs Aucnet: the same "5" isn't identical everywhere

Because each operator runs its own inspectors, calibration drifts between venues. TAA and CAA lean toward dealer-consigned stock and a reputation for stricter inspection — a TAA 4.5 is widely treated as roughly equivalent to a USS 5. Aucnet (AIS) uses independent third-party inspectors and is generally considered highly consistent. USS, as the largest network by volume, also has the widest inspector variance across its own venues — don't assume a USS Tokyo 4 and a USS Kyushu 4 were scored by the same eye. Treat every sheet as anchored to its own venue rather than assuming a universal scale.

What the sheet can't tell you

The grade is a cosmetic and structural-history snapshot at one point in time — it says little about mechanical condition, hidden corrosion under the sill covers, or whether an odometer reading is trustworthy on a car old enough that records have gaps. On anything you're actually importing, treat the auction sheet as the start of due diligence, not the end of it, and pair it with an independent inspection where one's available.

Why this matters for the eligibility clock, too

None of the above changes when a car becomes importable — that's a pure function of its manufacture month under the 25-year rule and the Import Eligibility Check. But the auction sheet is usually the only real condition data you'll see before a car changes hands across an ocean, which is why it's worth reading properly on chassis you're actually shopping for — like the R34 GT-R, JZX100 Chaser or Nissan Silvia S15.