For the longest time their strategy was to:
1. Issue bonds at near zero or even negative yield.
2. Buy US bonds.
The country is still one of the largest foreign US debt holders at $1.191T, and interest from this debt pays for a significant fraction of the interest on their own debt.
I don't understand. Why would anyone buy their bonds when the US bonds yield more?
If you issue debt at non-positive yield, then there is no interest on your debt to offset with the yield from US bonds.