Prisoners of the Yen

The watch dashboard

Which road is Japan on?

The book argues Japan can hold only two of three goals — cheap debt service, a defended yen, normalized rates — and that the choice of which to sacrifice is legible in a handful of readings. These are those readings.

USD / JPY

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10-year JGB yield

%

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BOJ policy rate

1.00%

Highest since 1995 · hiked 16 Jun 2026, held 31 Jul (8–1) · next meeting 17–18 Sep

Japan core CPI, y/y

1.8%

July 2026 · sixth month below the 2% target; ex-fresh-food-and-energy near 2.0%; the BOJ Outlook has inflation above target through the second half of FY2026

Nikkei 225

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Gold, $/oz (COMEX)

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Fed − BOJ policy spread

2.63pts

Fed 3.50–3.75% vs BOJ 1.00% · the gap that pulls the yen down

Japan gross debt

205% GDP

IMF 2026 · net ~134% · down from a 2020 peak of ~229% on the same vintage as inflation lifts nominal GDP

Market series: end-of-day closes, refreshed every 15 minutes. Policy and CPI readings are updated by hand after each release.

Reading the tape

The scenario map

Each row is an indicator; each column is the road it would point to. Track the yen's level and the Bank's hike path against inflation above all — fiscal stance is the swing that turns a given combination into A, B, or C.

Indicator Case A · consolidation Case B · debasement Case C · fiscal dominance
USD/JPY, post-interventionStabilizes or strengthens on credible disciplineGrinds weaker, ¥170+Defended by intervention, not rates; capital-flow measures appear
BOJ hike path vs. CPIHikes keep pace with or lead inflationHikes persistently lag inflationHikes halted or reversed despite an above-target print
10Y JGB yield & term premiumCompresses on restored credibilityElevated but orderlyDisorderly spike — or any new yield cap or purchase guidance
Fiscal stancePrimary-balance target restored; supplementary budgets shrinkSupplementary budgets stay large; debt-ratio metric retainedSpending sustained and the BOJ made to fund it
BOJ–government relationsIndependent, cooperativeQuietly accommodativeOpen friction; pressure on independence
Intervention frequencyInterventions ceasePeriodic, with diminishing effectHeavy, sustained, backstop-dependent (Fed FIMA repo)
Long-JGB demandHealthySoft but functioningBuyers' strike; failed auctions
Real wages vs. CPIPositive — relieves pressureNegative — sustains the squeezeSharply negative — a political forcing event

Reading the live feed against the matrix…

Current reading — Case B, unbroken. Read at the 31 August 2026 close; the tiles above are live and will have moved. The Bank has hiked to 1% and stopped; core CPI is running just below target while the yen sits near ¥159.75 after the largest yen-buying operation Japan has ever recorded — ¥15.4tn, about $96.5bn, published by the Ministry of Finance on 28 August — which markets unwound within weeks. Fiscal policy stays expansionary and unanchored. That combination — spending sustained, hikes cautious, the currency absorbing the strain — is the base case doing exactly what the book expects of it. The tell that would move the reading to Case C is not a weaker yen; it is any re-imposition of yield caps or purchase guidance in the JGB market.