Yes, he is indeed betting on a JGB rate rise and Yen devaluation, according to his statements and investor letters. It's the interest rate rise specifically that I don't really see the mechanism for, given the extent to which the BoJ has demonstrated willingness to simply buy all the bonds.
It's inevitable that the Yen gets massively devalued. That's pretty obvious. However, I still don't clearly see how that necessarily impacts JGB rates, as stated above. What's exactly is the mechanism? Furthermore, 50% base-money inflation for a few years, *without massive bond yield spikes* could absolutely be absorbed by an economy, especially a structurally deflating economy. It's the exponential feedback loop that high bond rates create which causes true hyperinflation.
So I don't think my original question has been answered yet. What's the mechanism that's going to spike rates? What's Kyle Bass's answer to that? Again - I'm sure there's a good answer; Kyle is no slouch.
You are right that the BoJ could buy up all bonds, and interest rates would not be affected, so it does not necessarily impact the JGB rates. But then the BoJ would have to print up a lot more base money to buy these newly issued bonds.
I don't know the numbers, but as japan has been deflating for many years now, I would guess that corporate and household debt is low compared to base money. While you can keep inflating money, you can't keep deflating the money supply. If all loans are paid off or defaulted on, you just get the base money (correct me if I am wrong).
Therefore, I think it is a reasonable assumption to make that if the BoJ keeps printing large amounts of money, this base money inflation will translate into higher price inflation (once monetary inflation forces overcome balance sheet reduction deflationary forces).
If interest rates are kept constant, this will make JGBs terrible investments (little yield in an inflationary environment), so the public will sell them, and the BoJ will have to buy all of it up. This would increase money supply drastically. I had a quick look at the numbers, and if I am using the correct ones, this would add roughly 500% to the monetary base. Hyperinflation much?
This could happen. Alternatively, if the BoJ feels that inflation is getting out of control, they could let interest rates rise, which would however bankrupt the government. So (unless they grow out of their problems), either they will hyperinflate their currency, or they will default on their bonds. Bass is taking both bets (so he is betting against them growing out of their problems, or against them maintaining the status quo for a prolonged period).