Importers of HS 9001.10 (optical fibers, optical fiber bundles and cables) from Japan actually paid 13.86% on the taxed portion of the value in 2026-06 — 12.93% across everything shipped, taxed or not. Measured from official duty receipts, not the rulebook: the statutory MFN base rate on this code is 6.7%. Over the window the rate on the taxed portion moved 6.7% → 13.86%, with the largest single step +6.1pp in 2025-05. Measured from official US duty receipts · as-of 2026-06 · confidence: measured, not modelled. The HTS base rate is 6.7% — importers actually paid 13.86%, so the trade-war overlay added 7.2 pts, measured at the border (not a summed rulebook estimate). Reproduce exactly: tariff_story(hs: "9001.10", origin: "Japan") · see it at trimtabist.com/tariffs
HS 9001.10. The schedule base rate is 6.7%; importers from Japan actually paid 13.86% on the dutiable value in 2026-06 — the trade-war overlay added 7.2 points, measured at the border. Measured, not modelled.
Over the window the collected rate moved 6.7% (2023-07) → 13.86% (2026-06), largest single step +6.1pp in 2025-05.
Japan's lower duty (12.93% vs 38.4%) lets it price up to 22.6% above China at the factory and still match on duty-inclusive customs cost. But on the LATEST measured prices, Japan actually lands cheaper — $56.7/kg vs $71.62/kg (duty in, freight out).
12 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 · 1 CBP ruling cite this code · reproduce: tariff_story(hs: "9001.10", origin: "Japan") via /connect. Not customs or legal advice.