3-b (max 20 points): Explain why yield curves in Japan changed drastically during the last year (from end-2021 to end-2022), and why yield curves differ in two products, JGB (Japanese government bond) and OIS (overnight index swap) under BOJ's YCC (yield curve control) policy. Consider also which yield curve, JGB or OIS, is more reliable in discussing the future course of monetary policy. Given that understanding on yield curve fluctuations, examine how BOJ's YCC policy influenced the Japanese economy in the last year using the AD-AS model. Note: OIS is an interest rate swap that exchanges the uncollateralized overnight call rate over a specified period and a certain fixed interest rate. Spot Rate Curves in Japan 1.4 (9%) 1.4 1.2 December 30, 2022 1.2 December 30, 2021 1.0 1.0 0.8 0.8 0.6 0.6 0.4 - * - JGB 0.4 0.2 -0-OIS 0.2 0.0 0.0 -0.2 -0.2 -0.4 -0.4 0 5 10 15 20 0 5 10 (maturity, year) 15 (maturity, year) 20