Two of the fastest marathon courses on earth, two very different races. Here's every stat, side by side, to help you pick.
Indicative — based on GPX data. Both courses normalised to start at 0m.
✓ marks the better number on that stat.
Both Boston and Tokyo are net-downhill Majors, but Tokyo's descent is far more pronounced — 445m of loss and a 250m net drop, against Boston's 400m of loss and 135m net drop. Boston's hills come in the second half (Newton, then Heartbreak Hill); Tokyo's downhill is spread more evenly across a point-to-point route past the Imperial Palace and Tokyo Tower.
Entry is the biggest practical difference: Boston needs a qualifying time, while Tokyo is a straightforward ballot open to any finisher-hopeful. Tokyo's course record (2:02:16) is also faster than Boston's (2:01:52 is actually marginally quicker — the two are close enough that either can claim bragging rights depending on the year). If qualifying-time prestige matters, Boston wins; if you want the easier entry route into a fast, downhill-assisted Major, Tokyo is the one.