Shinkansen busy days near xmas ?

My frnds (family group of ~15 !!) are on holiday in tokyo/osaka in December

I just realized they're planning on going from Osaka to Tokyo on the 24th December (that's Wednesday)

Whenever I go to tokyo I just go to shin Osaka, buy a ticket in the machine and go. I've never booked a shinkansen ticket. And I've never particularly travelled (on any form of transport) on Xmas eve

What do you think – is it typically packed? Is it like Golden Week?

(As it happens I've never travelled during Golden Week either! So I don't really know.)

If I myself have to go to tokyo on xmas or xmas eve (ie just 1 person, not a huge group) what's the deal?

by jonny_cheers