Importers of HS 8507.10 (lead-acid storage batteries, of a kind used for starting pis) from Japan actually paid 6.28% on the taxed portion of the value in 2026-06 — 6.28% 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 3.5% → 6.28%, with the largest single step +18.3pp in 2025-05. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 3.5% — importers actually paid 6.28%, so the trade-war overlay added 2.8 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "8507.10", origin: "Japan") · see it at trimtabist.com/tariffs
HS 8507.10. The schedule base rate is 3.5%; importers from Japan actually paid 6.28% on the dutiable value in 2026-06 — the trade-war overlay added 2.8 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 3.5% (2023-07) → 6.28% (2026-06), largest single step +18.3pp in 2025-05.
Japan's lower duty (6.28% vs 38.32%) lets it price up to 30.1% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, China actually lands cheaper — $3.33/kg vs $13.26/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 · reproduce: tariff_story(hs: "8507.10", origin: "Japan") via /connect. Not customs or legal advice.