Second Test, Kolkata, day four (close):
India 643-6 dec v South Africa 296 & 115-3
South Africa's hopes of survival depend heavily on the form of Prince and Amla
A combination of Hashim Amla and the weather held up India's second Test victory charge as South Africa reached 115-3 on a rain-interrupted fourth day.
Resuming on 6-0, still 341 runs behind, South Africa lost captain Graeme Smith for just 20 to Amit Mishra.
Jacques Kallis and Alviro Petersen also fell but only 34 overs were possible because of the weather.
Play was halted soon after tea, with Amla 49 not out, and India need seven wickets for victory on the final day.
The departure of Kallis, however, could yet prove key to the outcome after the in-form batsman - who scored 173 in South Africa's innings victory in the first Test - edged Mishra behind to wicketkeeper Mahendra Dhoni late in the day.
However, India will hope for better weather conditions on day five if they are to level the two-match series after rain ensured less than an hour's play was possible before lunch before bad light ended play two hours early.
"We still have very good chance to win provided we get a couple of sessions of play tomorrow," said India coach Gary Kirsten. "India is playing for its pride."
One man in the way of India and victory is Amla, fresh from his knock of 253 in the first Test, at the crease.
Still, with Mishra and spin bowling partner Harbhajan Singh causing problems throughout the day on a wearing surface, India remain favourites.
The former snared the first wicket of the day when he trapped Smith plumb in front with one that turned in slightly from off stump, before Harbhajan had Petersen, who had survived an earlier nick off Zaheer Khan, caught off an inside edge at forward short leg.
Kallis and Amla revived the tourists with a 57-run stand for the third wicket, but the former then got the thinnest of nicks onto a Mishra delivery to depart.
That leaves South Africa still 232 runs short of making India bat again and their hopes of a series win - and elevation to the number one spot in the world rankings as a result - in the balance.