"Boeing's checklists call for depressuriation of the aircraft and descent to 14000' or MEA/LSALT." - Bendy.
Buzzzzzzzz. Wrrrronnngggg.
Not all Boeing checklists.
"BTW unlikely to have VHF comms with anyone two hours out of Tokyo, even at normal cruise levels." - Bendy.
Double jeopardy......Wrrrronnnnnnnggg again!
VHF comms is provided for more than 4 hours flight time by
1 Tokyo Control, then
2 Okinawa Control, then
3 Manila.