Of course they would...

...Treasuries are also semi-formal contracts for security action. Japan is buying insurance against a more aggressive neighbor to the West. Conspicuously absent are cries of doom and warning about Japan "calling in loans" or willfully bankrupting the U.S.

More to follow on geopolitical security strategy as a PRC communique has outlined the maritime strategy and ambition of China.

Feb. 22 (Bloomberg) -- Lost amid government reports showing
that China reduced its holdings of Treasuries by a record amount
in December were data showing Japan increased its stake, a move
that may signal U.S. yields are peaking.

Purchases by Fukoku Mutual Life Insurance Co., Mizuho Asset
Management Co. and Daiwa SB Investments Ltd. helped push Japan’s
holdings to $768.8 billion, an increase of $11.5 billion. U.S.
government debt held by China fell $34.2 billion to $755.4
billion, Treasury Department figures showed Feb. 16.

Increased buying from a country that has lived through a
decade of recessions and deflation indicates Treasuries are a
relative bargain, with consumer prices in check and savings
rates rising. Investors in Japan, where households have built up
1,400 trillion yen ($15 trillion) of financial assets, are
attracted by U.S. yields that reached the highest since 2007
compared with Japanese government bonds.

“When the yield is high, people buy,” said Satoshi
Okumoto, an investment manager in Tokyo for Fukoku, which
oversees the equivalent of more than $60 billion. “The prospect
for inflation is quite limited. Consumer demand is limited” in
the U.S., he said.

The insurer bought as yields on 10-year Treasuries rose to
2.55 percentage points above those on similar-maturity Japanese
bonds in December, the most in two years, he said. While the gap
shrank to 2.45 percentage points last week, it’s still about 40
basis points above the average in that period.