Why Japan Isn't Getting Inflation?

I was just scrolling around economics on web trying to find good stuff to read, and dammm just came across the Gregory Mankiw blog... Well, for who doesn't know, he's a Harvard professor, he wrote and update the macro manual that we use as basis to study theories models... Arguably the best manual, but the Froyen is also really good.

And there was a very pertinent questioning there that I thought to share. If global inflation conditions are the same due to supply shocks, why is Japan not getting inflation? Also using this modern monetary theory (MMT) policies, right?!

It's on same lvl from before all this monetary expansionism and oil, energy, semiconductors shortages...

My personal hypotheses are that maybe they have made substancial transition to renewable energies and EV, so that cut operational and distribution chain costs, providing lower prices products than in global scale. They are known for been a tech inovative country, so they probably don't need to import that much from secondary sector and be exposed to external fiscal controls on exportations or fiat disparity... Another guess is that their population doesn't make nobrain spendings, while saves and invests intead, not throwing prices up due to increase in aggregated demand.

Its a short post, but here is the link:

https://gregmankiw.blogspot.com/2022/05/an-inflation-puzzle.html?m=1

I downloaded and gonna take a read on some MMT articles, also from others sources.