How to Book in Yoshiwara: What I Say and How I Confirm, Every Time
Short answer: give the date, time slot, number of people and name; book popular companions early; confirm once the day before and once on the day; use only the shop or this site's official channels — never make a private transfer first.

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Short answer: when booking, say "which day, what time, how many people, what name" all at once; book popular companions as early as you can; once it's set, reply to confirm the day before and on the day.
When I call or go through official channels myself, I first ask: is she still free in that slot, do they accept foreign guests, is there still pickup, and how do I pay. For a shop I'm unsure about, I don't rush to pay any deposit.
If you book with this site's help, add the official support account, confirm the schedule as instructed, and you'll end up with a booking order; on the day, follow the time and place on the order. Just keep the same name on the order throughout — don't pick anything too silly, as staff may call it out in front of others.
A lot of people skip these two confirmations, but I do them nearly every time: the day before, I check the booking still stands; on the day, before leaving, I say I'll be on time. If they can't reach you, some channels treat it as an automatic cancellation.
Rescheduling and cancellation rules differ by shop — tell them early. This site will never ask you to transfer to a private account to hold a slot — contact only through the published official channels or the shop itself.
Once booked, save the shop address in your map app and leave time to find your way, assuming "no pickup". The amount and any extras are whatever total the shop states when confirming.
Related: My First Time in Yoshiwara: From Booking to Leaving · Booking policy · Contact & booking