The Bank of Japan on Tuesday raised its benchmark interest rate by 25 basis points to 1 percent, the highest level in 31 years, citing inflation pressure from the U.S.-Iran war and a yen that has refused to leave the 160-per-dollar zone despite trillions of yen in intervention.
The quarter-point move, approved 7-1 with board member Toichiro Asada dissenting, is the BOJ's first hike since December and pushes Japanese borrowing costs to a level last seen in 1995. It accelerates a policy-normalization campaign begun in 2024 and reorients the world's fourth-largest economy around the assumption that imported energy costs, not deflation, are now the dominant risk.
What moved
The 10-year Japanese government bond yield climbed three basis points to 2.615 percent and the yen strengthened marginally to 160.22 against the dollar. The Nikkei 225 closed 0.46 percent higher, a muted reaction that reflected how thoroughly the hike had been priced in by economists polled by Reuters.
The BOJ also said it would keep tapering its government-bond purchases by 200 billion yen per calendar quarter before halting the runoff and holding monthly purchases at 2 trillion yen from April 2027.
The energy channel
Japan imported roughly 95 percent of its crude oil from the Middle East before the Iran war. Japan's producer price index rose 6.3 percent in May, its sharpest climb in more than three years, mostly on energy.
The central bank said the "price pass-through stemming from the rise in crude oil prices has been progressing at a relatively fast pace in business-to-business transactions, which could spread to an increase in consumer prices across a wide range of items."
Tai Hui, APAC chief market strategist at J.P. Morgan Asset Management, told CNBC the lopsided vote signaled the board is more attentive to inflation than growth, and that easing fears around the Strait of Hormuz gave the BOJ confidence to resume tightening. President Trump lifted the U.S. naval blockade of Iran on Sunday and set a Friday signing ceremony in Geneva to formally end the war.
The yen problem
Tokyo spent 11.7 trillion yen, roughly $73.5 billion, on currency intervention in May. The yen weakened again almost immediately and spent most of June pinned near 160 to the dollar.
"Intervention without changing domestic monetary policy is like tapping the brake while keeping your right foot firmly on the accelerator — at best, your passengers have a little fun, at worst, you're burning through your brake pads," Jesper Koll, expert director at Monex Group, told CNBC.
The dissent
Asada's lone vote against reflects a real constraint: Japan's core consumer price index rose just 1.4 percent in April, the lowest reading since March 2022 and the fourth straight month below the 2 percent target. The central bank credited the low figure to government measures including a 3 trillion yen supplementary budget passed by Prime Minister Sanae Takaichi's administration, the removal of the gasoline tax and free high school tuition.
Strip those subsidies out and the inflation picture looks hotter. Leave them in and the BOJ has just tightened into a headline rate well under its own target.
The taper path now runs alongside a rising policy rate, with monthly JGB buying set to settle at 2 trillion yen from April 2027.