Guys, it's pretty clear if you know geography that they fused two into one to create the fake country of Liechtenburg.
People have already detailed Liechtenstein here, but the other country of note is Luxembourg. Luxembourg is a famously wealthy (per-capita, at least) European country, fairly small (obviously not as small as Liechtenstein), currently has a single princess that is about the right age (she turned 29 this year), and that very princess actually visited Japan in 2017 as one of very few noteworthy foreign trips she's ever taken. https://en.wikipedia.org/wiki/Princess_Alexandra_of_Luxembourg#Activities