Yen

The lobster is sometimes said to be immortal. It shows almost no sign of senescence: it does not weaken or lose fertility with age, and its cells keep dividing as though the years did not count (Smithsonian). But not ageing is not the same as not dying. The lobster dies. It dies not of old age but of the very mechanism of its growth. A lobster can grow only by shedding its whole shell in a moult, and each moult costs exponentially more energy as the animal gets larger. Between 10% and 15% of older lobsters die each year from a failed moult, and in time they stop moulting at all to conserve energy (Smithsonian, citing Maine’s Department of Marine Resources). The old shell then wears, bacteria get in, and scar tissue fixes the body to the shell. Trapped in the shell it will not shed, the animal rots. It dies because it stopped shedding, not because its time was up. ...

The speculative yen short that had built to a 19-year high fell for the first time in the week to 7 July. On the Commodity Futures Trading Commission’s positioning data, the leveraged-fund net short in the yen, futures and options combined, went from −137,828 contracts on 30 June to −104,231, a cover of 33,597 in a week. The last time the book ran heavier was the first half of 2007. Yet the yen barely moved. ...

In 2025 Japan ran a current-account surplus of ¥31.9trn, a record and the second in a row. Yet the yen has not stopped falling. Even after the Bank of Japan raised rates in June 2026, the currency trades around ¥161 to the dollar, close to its weakest since 1986. A record creditor’s currency sits at a four-decade low. Unless that contradiction can be resolved, the question every market participant is asking has no answer: where does the yen go next? ...

Speculative yen shorts have piled up to a record. And yet the options market is pricing the summer as if almost nothing will happen. The two do not belong in the same world. The latest CFTC data, for positions as of 2 June and released on 5 June, put the net yen short held by leveraged funds (futures and options combined) at 105,136 contracts, a further 18,887 deeper on the week. Each contract is ¥12.5m, so the notional yen sold runs to roughly ¥1.3tn. Open interest rose by 89,327 contracts to 559,092. Asset managers are short as well, by 62,814 net: the crowd is not one desk. The powder is close to full. ...

Donald Trump extended the Israel-Lebanon ceasefire by three weeks on Thursday, pushing the 26 April expiry to mid-May. For speculators holding a yen short built to pay out on that discrete binary, the event has not dissolved; it has moved, into the same fortnight as Scott Bessent’s scheduled Tokyo stopover on his way to Mr Trump’s summit with Mr Xi in China. The shift matters because the dollar-yen floor at 160 is held not by any change in Japanese interest rates but by a new bilateral arrangement. Satsuki Katayama, Japan’s finance minister, threatens intervention; Mr Bessent, US treasury secretary, endorses her by declining to contradict her in public. This is the intervention-acquiescence model: US tacit consent to Japanese currency defence, in lieu of the January pressure on the Bank of Japan to raise rates. ...

There are two kinds of statement a finance minister makes: the spoken and the withheld. When America’s treasury secretary, Scott Bessent, met his Japanese counterpart, Satsuki Katayama, in Washington on 15 April, the unspoken carried the weight. When the two last met, in January, the Treasury’s readout noted that Mr Bessent “emphasized the need for sound formulation and communication of monetary policy”, diplomatic code for pressing the Bank of Japan to raise rates. That sentence is absent from the April readout. Ms Katayama, for her part, told reporters that the two ministers had not discussed monetary policy. ...

Scott Bessent worked at Soros Fund Management across two stints between 1991 and 2015, doing one thing supremely well: spotting the moment when a central bank had mispriced risk and the speculative position on the other side was too large to unwind gracefully. When that moment came, the correction was violent. The people positioned for it made fortunes. Bessent was one of the best. Now he runs the US Treasury. Japan holds roughly $1.2 trillion of American government debt, the largest foreign position — a mix of official reserves and private institutional holdings. If the yen weakens far enough, the private side of that equation starts to shift: life insurers and pension funds find hedging costs too high to justify holding US bonds, and new purchases dry up. US borrowing costs rise. ...

Japan’s budget passed. The ceasefire is collapsing. Katayama’s intervention window is open for the first time since she took office.

In 1274, a Mongol-Korean invasion force landed at Hakata Bay in northern Kyushu. Japan’s samurai, trained for single combat, were routed by massed formations wielding gunpowder weapons they had never seen. A storm forced the invaders to withdraw, but the lesson was plain: the existing military model would not survive a second attempt. The Kamakura shogunate spent the next seven years preparing. It built a 20km stone seawall along Hakata Bay, developed small-boat night-raiding tactics and established Japan’s first permanent coastal defence force. When a far larger invasion arrived in 1281, the seawall held. The Mongol fleet sat offshore for weeks, unable to land. Then a typhoon struck and finished what Japanese preparation had started. ...

Japan holds 254 days of oil in reserve. That number has been repeated so often since 28 February that it has become a kind of talisman, proof that the country can absorb anything the Strait of Hormuz throws at it. It is also misleading. On 16 March, Prime Minister Takaichi ordered the largest oil reserve release in Japanese history: 80 million barrels, equivalent to 45 days of domestic consumption. The draw came from both private and government stockpiles and was coordinated with a 400-million-barrel IEA-wide release across 32 member nations. Japan’s contribution was the second largest after the United States. ...