The flow story behind KRW weakness has transitioned from overseas buying by domestic retail to domestic selling by foreigners. Two other factors help inform the exchange rate: correlation with the JPY and, perhaps, a BOK that is late in hiking given the huge acceleration in NGDP growth.

The sharp rise in inflation since March slowed in June, and the BOK expects a drop in July. But cost-push from the surge in semi prices is feeding into CPI, and the BOK also expects "expanding demand pressures" from the economic recovery to drive inflation from here.

There are signs of a broadening of the cycle, with construction past the worst, capex rising, and the labour market bottoming. However, while services activity has been strong recently, retail sales are still sluggish, and industrial production is going sideways.

Business sentiment is middling, and the gap between large and small firms looks K-shaped. However, consumer confidence is quite strong, and the BOK has argued that sector disparities aren't an issue for monetary policy. Falling oil prices do lessen inflation risk, but also boost GDP growth.

The sharp rise in import and export prices of recent months eased in May. But that leaves export prices at the highest level since the brief spike in 2008. That brings inflation for ROW and an income boost for Korea. With spot semiconductor prices still rising, neither trend is yet exhausted.

BOK governor Shin Hyun Song gave a speech on Friday to mark the 76th anniversary of the bank's founding. It was short, but worth highlighting, because he sounded more confident about the outlook, and downplayed the significance of uneven growth as a factor for monetary policy.

Korea is experiencing a large positive terms of trade. As that isn't being accompanied by any KRW appreciation, the result is enormous growth in KRW nominal indicators. Not all sectors are benefiting. But for monetary policy, the strength of nominal growth is impossible to ignore.

The corporate surplus is surging, and at first glance, that supports the idea that the semi-led cycle won't trickle down. However, while the labour share is falling, the rise in national incomes has been so strong that growth in labour compensation is accelerating. That should support spending.

KRW weakness was blamed on USD strength, then CNY weakness, then JPY weakness. Flows have gone from NPS, to domestic retail, to foreigner institutional. These rationalisations feel a bit like moving the goalposts. But weak KRW does have implications, one likely being a more hawkish BOK.