‘재산분할’에 관한 한국과 일본의 비교법·법경제학적 분석

A Comparative and Law-and-Economics Analysis of Marital Property Division in Korea and Japan

This article shows that, despite similar civil-code texts premised on the separate-property regime, Korea and Japan diverge in practice on how they treat separate (individual) property at divorce. Japanese courts consistently exclude the corpus of separate property and focus on liquidating jointly formed marital gains, whereas Korean lower-court practice has expanded division to “substantive separate property.” This divergence alters rights boundaries, predictability, and transaction costs, thereby shaping partner selection, marriage incentives, and potentially fertility outcomes. From a law-and-economics perspective, Coase and Kaldor–Hicks reasoning suggests that expansive ex-post redistribution raises ex-ante avoidance costs and inefficiency; incomplete-contract/hold-up logic explains weakened investment incentives. Under Prospect Theory, salient loss aversion renders marriage a transaction with perceived downside risk when separate-property division is expected, lowering expected utility of marrying. A policy implication is to clarify the exclusion of the separate-property corpus while using reimburse-ment/appreciation accounting and distinct support devices to address equity, improving both predictability and efficiency.