How do I use JAL Touch & Go without doing a separate airport check-in?

What this answer depends on

• Eligible JAL Japan domestic Touch & Go bookings; not international Home Print or Mobile Boarding Pass procedures
• The practical check is the Touch & Go indication next to the seat, not merely that a ticket was purchased. JAL requires booking, payment and seat selection to be completed for the described route. Certain fares and codeshares are excluded. Resolve a missing eligibility indication before assuming that a counter visit is unnecessary.
• JAL supports the stated two-dimensional barcode and IC-based options. To use the membership IC route, the membership information must be registered in the reservation. At security, the scan produces a Boarding Information Slip; the same underlying credential is used again at the gate. Do not switch casually between an unregistered card and a phone image.
• JAL tells travelers to keep the slip until arrival and present it when reentering security. Its domestic instructions require passage through security at least 20 minutes before departure and arrival at the gate at least 10 minutes before departure. Those are stage-specific requirements, not a recommendation to reach the terminal only 20 minutes before a flight.
• JAL domestic Touch & Go eligibility is shown beside the seat after booking, payment and seat selection, subject to fare/codeshare exclusions.
• JAL Touch & Go uses supported barcode/IC credentials; IC membership must be registered in the booking and the same credential used at security and gate.
• Security scanning issues a Boarding Information Slip to keep until arrival and present for security reentry.
• JAL domestic Touch & Go instructions require security passage by 20 minutes and gate arrival by 10 minutes before departure.