Itinerary
Days run top to bottom, each with a base city. Change a city and the planner treats that day as a move, costs the journey and tells you what is left of the day. The strip between two stops sets how you travel that leg, which is what the map draws.
Trip brief
Everything that is not the day-by-day: what the trains cost, what you must book and by when, your confirmations, the money, and the things worth knowing before you land.
Rail and passes
The planner reads the base city of every day, works out the journeys between them, prices them, then tests all 17 passes against that exact route.
Timing
In Japan the binding constraint is usually lead time, not money. Everything below counts back from your start date.
Reservations
Confirmation numbers and seat numbers in one place, so you are not searching an inbox on a platform.
Money
Built from your actual itinerary — the journeys you are taking and the entry fees of the stops you scheduled — not a generic daily figure.
What you actually spent
Know before you go
The things that are genuinely different, and that cost you an awkward moment or an hour if nobody mentions them.