I have just booked a JAC flight on the JAL domestic web site (KIJ-ITM May 28). Some friends want to book the same flight, but it is no longer showing availability on the JAL site. I imagine that in reality it is wide open (hardly any seats appear occupied), but JAC does not show availability on Expert Flyer.

Does anyone know how this works? Are JAL likely to provide more availability, or can the flight now only be booked on the JAC site (which is not available in English)?