USD/JPY printed 152.89 at around 03:20 UTC yesterday — in Tokyo hours, on Japanese wage data, with the yen at its strongest against the dollar since February. By the New York close it was back between 153.75 and 154.00, having traded as high as 154.42. The low of the entire six-session yen move was made in the Tokyo session, and every hour since has been giveback. What stopped it was not Japanese. Brent went to $99 after strikes on Saudi energy facilities, and the US 10-year yield topped 4.8%.
The sequence matters more than the level
Reconstruct yesterday in order, because the order is the information.
- Tokyo morning — USD/JPY broke 154 and kept going. Minkabu's session desk had it in the 152 handle by 11:35 JST (02:35 UTC) and marked 152.89 at 12:20 JST (03:20 UTC).
- London — the pair held the low 153s. Our own 11:30 UTC note had it at 153.53 and heading towards 153.00.
- New York — it went the other way. FXStreet marks the high of day at 154.42 and the close around 153.75; Gaitame.com's morning note has the daily close at 153.98. Call it the mid-to-high 153s. Either way, the dollar took back roughly a hundred pips of a move that had run 650 pips in four sessions since 2 September.
Three sources now agree on 152.89 as the low — FXStreet, Gaitame.com and Minkabu's intraday desk. In our pre-US note yesterday we declined to publish that figure because only one vendor had it. It has since been corroborated, so we are using it, and we are flagging that we were right to wait.
The useful part is that Asia set the extreme and the West unwound it. If your system trades the Tokyo session on the assumption that Asia ranges and London trends, yesterday inverted that. Asia produced the day's directional extension and New York produced the mean reversion.
Brent at $99 is a Japan story before it is an oil story
Yemen's Houthis struck multiple Saudi energy facilities on Tuesday, including Jizan, which houses a 400,000 barrel-per-day refinery. Saudi authorities called it a dangerous escalation and reported 73 people wounded. Brent settled around $99.00, up 2.06%, after touching $99.22 — its highest since 24 July. WTI settled near $94.41, up 3.2%, after a high of $94.60, the highest since 8 June. Two independent outlets carry identical figures, so we are treating them as solid.
Now put that next to a number from the Japan Center for Economic Research: 95.9% of Japan's crude oil came from the Middle East in FY2024, the highest share since FY1960, and 73.7% of Middle East crude bound for Japan transits the Strait of Hormuz. Saudi Arabia and the UAE each supplied over 40%.
That is not a background statistic. It is the mechanism by which a missile in Jizan becomes a yen quote in Tokyo. Japan pays for oil in dollars and earns in yen. A ten-dollar move in Brent is a direct terms-of-trade tax, and it arrives through the trade balance long before it arrives through anyone's inflation forecast. Among the G10, no currency has a worse import structure for this shock. That is why the yen stopped rallying at 152.89 while nothing about the Bank of Japan changed.
This complicates the BOJ. It does not simplify it.
There is a tidy argument going around — TradeTheNews put it on FXStreet yesterday morning — that yen appreciation does the Bank of Japan's job for it. A stronger yen suppresses imported inflation, so the Bank can deliver 25bp on 18 September rather than something larger. The same note reads the softer Q2 GDP revision as consistent with 25bp rather than 50bp. That is a reasonable read, and it was a reasonable read at 06:00 UTC.
It is less reasonable at $99 Brent. The two channels now pull in opposite directions inside the same policy horizon. The currency is disinflationary at 153; the oil bill is inflationary at 99. Whether the net is disinflationary depends on the path of both over the next nine days, which nobody knows.
What we would say plainly: an outcome that was being treated as a one-way conditioning story — strong yen, easy decision — is now genuinely two-sided. If you had convinced yourself that 18 September was a low-variance event because the currency was doing the work, revisit that. A fully priced hike with an ambiguous inflation backdrop is a wider distribution than a fully priced hike with a clean one, and the price of the option should reflect it.
What this does to Tokyo-session sizing today
Yesterday's range in USD/JPY was 152.89 to 154.42 — 153 pips, and a meaningful part of it printed inside Tokyo hours. If you run an Asia-session mean-reversion book calibrated on a 40 to 60 pip Tokyo range, your position sizing is now derived from a distribution the market has stopped drawing from. That is a stop-distance problem, not a direction problem.
Gaitame.com's analyst desk publishes an expected range for today of 152.90–154.50, with selling expected into 154 and the inability to reclaim 155 read as evidence the yen phase is intact. That is one Japanese desk's view and we present it as such. But the width is the point: they are forecasting a 160-pip day as normal. Three weeks ago that would have been an event day.
Two concrete consequences for a system trader:
- Net your yen exposure as one position. USD/JPY, EUR/JPY, GBP/JPY and AUD/JPY are not four uncorrelated trades this week. If oil is the shared driver and Japan is the shared importer, they are one trade with four tickets.
- Oil is now an FX input, not a commodity you do not trade. If your correlation filter does not have a crude term in it, it is currently blind to the thing that reversed the yen. That is a filter design question, and it does not require you to have any view on oil.
We wrote yesterday that WTI near $90 was a correlation problem before it was an oil trade. It is now $94 and the correlation showed up in the yen. We would rather record that than pretend it was obvious.
What this does not tell you
It does not tell you the yen move is over. A 650-pip run giving back a hundred pips is normal, and the 152.10 low from 27 January is still the level that matters technically. FXStreet reads a hammer at 153.70 as a rebound tease; that is a chart pattern, not a forecast, and it has no predictive content on its own.
We do not have a live Tokyo order book we trust. Traders Web FX's USD/JPY page is stamped 08 September 06:22 against a quoted spot of 154.36 as of 7 September — two days behind price. We have now found it stale at three consecutive slots and we are not publishing levels off it. If you use that page, check the timestamp before you use the numbers.
We do not know whether Saudi output is actually impaired. Aramco had issued no statement at the time of the reports we read, and damage was still being assessed. The oil price is trading a risk premium and an assessment, not a confirmed supply loss. If the assessment comes back benign, the input that reversed the yen disappears, and it disappears fast.
We also do not know how much of yesterday's New York bounce was oil and how much was the 10-year going through 4.8%. Both happened in the same window. Anyone telling you the split with confidence is guessing.
Related
- FX event calendar — China CPI and PPI at 01:30 UTC today, the 10-year note reopening at 17:00 UTC, and Thursday's ECB stack.
- Signals
- Expert Advisors
