A deluge of net bowlers lined up near India's practice nets on Wednesday afternoon at the Eden Gardens, waiting patiently for their turn as Kuldeep Yadav and Washington Sundar got started. Jasprit Bumrah and Mohammed Siraj were only warming up in the adjacent nets while the top-order got stuck into a steady diet of spin. Beside Kuldeep's left-arm wrist spin and Washington's off-spin, the net bowlers offered left-arm orthodox and right-arm variations that turned the ball both ways.

Batting in spin-specific nets is routine for any top-order, but it has carried added significance here ever since New Zealand came and rattled India last year. For any team touring from outside the subcontinent, those 2024 heroics have become the blueprint to swear by. India's top-order looks different now, but the memory of losing 37 wickets to spin in three Tests still lingers, and every opponent doing its homework knows it.

To India's credit, they looked far more assured against West Indies last month, losing only 11 wickets to spin and collectively averaging 63.09 against it. But there's still a lesson for South Africa in all the recent numbers. India lost a wicket every 17.5 overs of spin against West Indies, but when they went up against New Zealand's higher-quality attack, that figure dropped to 5.4. No visiting team's spin attack managed a better strike rate than New Zealand did (33.8) in a single series in 89 bilaterals in India. The pattern is clear enough for anyone looking.

South Africa, like New Zealand of 2024, arrive in India with recent subcontinental experience behind them. While New Zealand warmed up in Sri Lanka before stunning India at home, South Africa come fresh from two Tests in Pakistan. They even went one better by pulling off a remarkable win in Rawalpindi, where Keshav Maharaj claimed seven wickets in the first innings. In India, he will be flanked by Senuran Muthusamy and Simon Harmer. This spin-heavy make-up of South Africa's squad is not lost on the Indian management.

"It's a little bit like playing against a subcontinent team. You never actually normally worry about the pace attack first. And I'm pretty sure they'll go with two seamers and three spinners," India's assistant coach Ryan ten Doeschate noted, when asked if his team could expect a very different South African challenge.

South Africa tried a three-spinner formula the last time they toured India in 2019 too, but abandoned it after the first Test in Vizag. This time, though, recent evidence suggests they might stay the course. In Pakistan, their spinners outbowled the hosts - 239 overs to 227, while their pacers sent down a little over a third of that (81 overs)

Interestingly, South Africa's only two Test wins in India since 2001 came when Dale Steyn tore through batting line-ups (Ahmedabad 2008 and Nagpur 2010). They now have Kagiso Rabada leading the attack on his third India tour, but the narrative remains around the spinners doing all the heavy-lifting.

"I think it gives us a lot of confidence," South Africa head coach Shukri Conrad said of his team's spin combinations. "I think previously, and this is not saying that we didn't have good spinners in the past, but certainly we think we've got a better pack of spinners now. Obviously, Keshav, Simon and Sen, so I think it gives us a lot of confidence. we feel that we've got the armoury to obviously challenge India in that respect as well."

India have also spoken about playing spin with a touch of caution ever since New Zealand reminded them how vulnerable even they can be at home. "But that is the challenge when you're playing in the subcontinent," ten Doeschate offered. "It's something as a team that we need to get better. We addressed it early on. We've come up short a few times. So it's a great challenge. Hopefully we've learned from the New Zealand series. We've put some plans into place on how to play spin. It's going to be so important over these two games, particularly how well they did in Pakistan about four weeks ago."

Intriguingly, South Africa's spin indulgence comes just as India appear to be moving away from rank turners at home - a shift seemingly shaped by last year's lessons. South Africa thrived on spin in Pakistan but might find it harder to replicate that success here. India, for their part, handled West Indies' spinners far better, yet must prove they can do the same in South Africa. The two sides now meet in that space between expectation and reality, with the potential for an all-timer of a series.