Japan has been a principal player in international assistance to Afghanistan, ranked second only to the United States in its overall financial assistance disbursed since 2002. This article places a spotlight on the largely underappreciated subject of Japan's primarily non-military and economic infrastructure-oriented assistance by articulating three major characteristics of Japan's policies and practices in Afghanistan — relatively large disbursements for reconstruction programmes, designating disarmament, demobilisation, and reintegration as Japan's niche area, and substantial reliance on international organisations for fund disbursement. Despite its comparatively advantageous position vis-à-vis other donors, Japan has faced a set of institutional and structural impediments to carrying out effective stabilisation and reconstruction assistance, not just in Afghanistan, but also in other conflict-prone and fragile societies. These include, among other things, the shortage of expertise, bureaucratic pressure for ‘cash burning’, inter-agency coordination problems, and waning political interest. As a result, this article argues that Japan has been underequipped to provide peacebuilding assistance on the large scale it committed in Afghanistan. If Tokyo hopes to safeguard its major investments in Afghanistan, it needs to revive the substantive political leadership it exercised in the early years of Afghan peacebuilding.