DESIGN: A Stock-and-Flow simulation model was used to project smoking prevalence and mortality from 2018 to 2050 under eight different scenarios: (1) maintaining the 2018 status quo, (2) implementation of smoke-free policies, (3) tobacco use cessation programmes, (4-5) health warning about the dangers of tobacco (labels, mass media), (6) enforcement of tobacco advertising bans or (7) tobacco taxation at the highest recommended level and (8) all these interventions combined.

RESULTS: Under the status quo, the smoking prevalence in Japan will decrease from 29.6% to 15.5% in men and 8.3% to 4.7% in women by 2050. Full implementation of MPOWER will accelerate this trend, dropping the prevalence to 10.6% in men and 3.2% in women, and save nearly a quarter million deaths by 2050. This reduction implies that Japan will only attain the current national target of 12% overall smoking prevalence in 2033, 8 years earlier than it would with the status quo (in 2041), a significant delay from the national government's 2022 deadline.