Asian stock markets soared Friday as tech shares rebounded and the yen jumped following apparent currency intervention. South Korea's Kospi, which had tumbled 17 per cent over three sessions, gained more than 14 per cent in morning trading. Chipmakers SK Hynix jumped as much as 25 per cent, while Samsung Electronics rose up to 22 per cent.

Sentiment improved after SK chair Chey Tae-won bought about 3,600 shares for $3.2mn, seen as a confidence vote after the company reported a sixfold earnings increase. Japan's Nikkei 225 rose up to 5.4 per cent, with semiconductor stocks leading. The yen strengthened as much as 3 per cent Thursday, holding above ¥160 versus ¥163 previously.

Traders confirmed Japanese government intervention, the first since April-May when ¥11.7tn ($73bn) was spent. Co-ordination with US authorities may help sustain gains. Analysts at Citi and Deutsche Bank noted limited dollar-yen upside near-term, though some clients test resolve with shorts targeting ¥162.

Moves precede a Bank of Japan policy meeting where rates are expected to hold at 1 per cent. Strategists warn turning dovish post-intervention would undermine its effect.