Some general information on driving: https://www.japan-guide.com/e/e2022.html

You definitely need an IDP, you can get it in advance at home. Since you're only on holiday, you don't need a JAF translation or a Japanese license (Australia is part of the 1949 Geneva Convention on road traffic, so your domestic license is recognized).

You will need a Carnet de Passage - Grant's link explains those.

Navigating is a bit tricky if you don't read Japanese, but not impossible, especially with Google Navigation. Rules of the road are generally the same as anywhere in the world, to my knowledge there is no turn on red, and no Melbourne-style hook turns.

I will point out that as Japan is a country with an extremely efficient public transport system, and intercity trains are made remarkably affordable for tourists using the JR Pass (much more affordable than for locals!), and pretty much every major train station has car rental agencies just outside, and Japan has a unique domestic vehicle market, then I would urge you to consider the efficiency of shipping your vehicle back and forth at a cost of many thousands of dollars, as opposed to:

1) Renting a tiny motorhome of the sort that you definitely could not experience at home to go into the Japanese countryside, e.g. https://www.japancampers.com/motorhome.html

2) Renting an iconic Japanese performance car to drive on recommended mountain roads, e.g. https://fun2drive-japan.com/car-tour..._hakone_drive/