JFR-rg: A New Macroeconomic Framework for High-Debt, Low-Growth Economies under Financial Repression

Abstract: Standard macroeconomic frameworks have correctly identified Japan's government debt - now exceeding 240% of GDP - as carrying substantial fiscal risk. Yet real-time FRED data from 2013 to 2026 present an empirical record inviting a complementary perspective: debt ratios have stabilized, nominal GDP has exceeded 670 trillion yen (SAAR), and unemployment has remained approximately 2.6-2.7%. This paper formalizes these channels through the Japanese Financial Repression r-g (JFR-rg) model. Building on Blanchard (2019), the framework incorporates a financial repression bias (epsilon_t = pi_t - r^n_t, directly observable from FRED) and a non-linear exchange-rate channel. Three theoretical contributions extend the existing literature: (i) the Debt Sustainability Corridor, a geometric characterization of stability in (epsilon_t, g^n*_t) space; (ii) the Normalization Ratchet, a path-dependence theorem showing that temporary policy errors generate persistently higher debt trajectories; and (iii) the Captive Financial System Parameter (phi_t), which endogenizes the institutional precondition for JFR-rg stability. Appendices H-L provide supporting empirical evidence (VAR, ARDL, Local Projections) demonstrating the framework's claims are empirically disciplined and falsifiable. Core propositions derive from the consolidated government budget identity (Layer L1) requiring no causal identification; identification concerns apply only to the empirical Layer L2. Counterfactual simulations illustrate a Normalization Trap: aggressive rate hikes can produce counterproductive debt dynamics. For high-debt, low-growth economies sharing Japan's institutional characteristics, strategically deploying the resulting Repression Dividend into productivity-enhancing investment may represent a regime-contingent equilibrium possibility - conditional on the captive system threshold being maintained.