It is necessary in the following situations:
Your ticket nunber depends on the ticket type and your purchasing method.
You can find your ticket number in the automatic email message sent when you finalized your domestic award ticket transaction.
Please check the section labeled Electronic Ticket Itinerary/Receipt.
Email subject:[JAL] eチケットお客さま控え - Electronic Ticket Itinerary/Receipt
Go to Manage booking to find your ticket number before your flight date by following the steps: