Importers of HS 8507.90 (of lead-acid storage batteries) from Japan actually paid 13.19% on the taxed portion of the value in 2026-06 — 13.14% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 3.5%. Over the window the rate on the taxed portion moved 3.4% → 13.19%, with the largest single step +11.4pp in 2025-06. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 3.5% — importers actually paid 13.19%, so the trade-war overlay added 9.7 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8507.90", origin: "Japan") · see it at trimtabist.com/tariffs
HS 8507.90. The schedule base rate is 3.5%; importers from Japan actually paid 13.19% on the dutiable value in 2026-06 — the trade-war overlay added 9.7 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 3.4% (2023-07) → 13.19% (2026-06), largest single step +11.4pp in 2025-06.
Japan's lower duty (13.14% vs 37.58%) lets it price up to 21.6% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $12.55/kg vs $24.01/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 · 5 CBP rulings cite this code · reproduce: tariff_story(hs: "8507.90", origin: "Japan") via /connect. Not customs or legal advice.