Importers of HS 8504.40 (suitable for physical incorporation into automatic data proc) from Japan actually paid 10% on the taxed portion of the value in 2026-06 — 4.78% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is Free. Over the window the rate on the taxed portion moved null% → 10%, with the largest single step +10.1pp in 2025-04. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is Free — importers actually paid 10%, so the trade-war overlay added 10 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8504.40", origin: "Japan") · see it at trimtabist.com/tariffs
HS 8504.40. The schedule base rate is Free; importers from Japan actually paid 10% on the dutiable value in 2026-06 — the trade-war overlay added 10 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved % (2023-07) → 10% (2026-06), largest single step +10.1pp in 2025-04.
Japan's lower duty (4.78% vs 33.49%) lets it price up to 27.4% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $29.14/kg vs $31.14/kg (duty in, freight out).
14 Chapter-99 measures name Japan; scope mapping is partial (several annexes are PDFs) — absence never means exemption. They do not sum, and some are product-specific — the collected rate above is the composed truth.
All goods from Japan · the whole tariff ledger · 20 CBP rulings cite this code · reproduce: tariff_story(hs: "8504.40", origin: "Japan") via /connect. Not customs or legal advice.