TL;DR
* Japan’s power sector has moved from regional monopolies to full retail liberalisation (2016) and legal T&D unbundling (2020).
* New markets—day-ahead (JEPX), Capacity, and Long-Term Decarbonisation Auctions—aim to ensure liquidity, reliability and climate targets.
* Recent fuel-price shocks exposed retailer fragility, grid bottlenecks, and dominance