* Auto shares rally after Hyundai Motor Q1 results
* Chemicals lead, SK Innovation up 4.5 pct
* Steels and metals up on firmer gold price
* Foreigners sell for 10th day but local institutions buy
By Somang Yang
SEOUL, April 25 (Reuters) - South Korean shares closed higher on Thursday, helped by a relief-rally in auto shares after Hyundai Motor's earnings met forecasts.
The Korea Composite Stock Price Index (KOSPI) rose 0.8 percent to end at 1,951.60 points, a three-week high.
"The index rose as auto shares rallied when Hyundai Motor's results met expectations," said Kim Byung-yeon, an analyst at Woori Investment & Securities.
"Because of the yen's tumble, we knew profits were going to suffer, but at least the top line held, with sales up modestly."
Shares in Hyundai Motor closed up 5.7 percent, their biggest daily percentage gain in one year, while affiliate Kia Motors climbed 4.4 percent.
Chemicals and metals also staged a comeback on firming oil and gold prices.
The petro-chemicals sub-index rose 1.2 percent, with refiner SK Innovation up 4.5 percent.
The steels and metals sub-index rose 1.8 percent, with Hyundai Steel gaining 4.3 percent.
Overall, 441 shares advanced while 374 declined.
Early on Thursday, South Korea said its economy grew a seasonally adjusted 0.9 percent in the January-March period from the previous quarter, the fastest in two years and far above market expectations. The surprising growth dented expectations for a rate cut by the Bank of Korea.
Local institutions net bought 168 billion Korean won ($150.32 million)worth of KOSPI shares, insulating the main board from a tenth session of foreign selling.
The KOSPI 200 benchmark of core stocks closed up 1 percent, while the junior KOSDAQ edged 0.8 percent lower.
Move on day +0.84 percent
12-month high 2,031.10 2 January 2013
12-month low 1,769.31 25 July 2012
Change on yr -2.28 percent
All-time high 2,231.47 27 April 2011
All-time low 93.10 6 January 1981 ($1 = 1117.6500 Korean won) (Editing by Kim Coghill)