I departed via HND in mid April also, the queues were crazy but there was a fast track option which required pre-registering using some digital terminals behind the JAL F check-in area.

We weren't proactively told about it when checking in at the JAL F counter (OWE travelling JL J) but only mentioned after we asked if there was any sort of priority available.

I'm not sure if the digital terminal supported all passports & airlines, but in any case it helped us skip a 1000+ person queue and hop into a line that was max 30 people long.