The allrounder came to the crease with the tourists 45 for 4 before lunch, and she only departed shortly before the close of play
Taunton (first day of four): South Africa 284, England
Marizanne Kapp starred at Taunton to take South Africa from a position of first-innings jeopardy to a more than respectable total after being invited to bat first in their first Test since 2014.
The allrounder came to the crease with the tourists 45 for 4 before lunch, and she only departed shortly before the close of play, once she had navigated her side towards a position of such respectability that she could afford to open her shoulders as she marshalled the tail towards 300.
She eventually fell, slapping Lauren Bell to Tammy Beaumont at mid-off for 150, having gone to her hundred by slashing over a slip cordon that had long-since shrunk in accordance with the chancelessness of a tremendous individual effort. She stroked 26 fours – many of which raced through the off-side – during her vigil.
What South Africa's day would have looked like without her contribution didn't bear thinking about; only Sune Luus (27) and Anneke Bosch (30) passed 16, but she received plenty of support from her lower order. Ninety-one of her runs followed the fall of the sixth wicket, dominating useful stands with Nadine de Klerk, Sinalo Jafta and Tumi Sekhukhune.
Rather than counterattack, Kapp simply took the scoring opportunities as she saw them, having waited eight years since her last Test appearance for this occasion. She made the highest score by a No.6 in women's Test cricket.
England handed debuts to Emma Lamb, Alice Davidson-Richards, Issy Wong and Bell, with Freya Davies and Charlie Dean left out on a surface that is not expected to break up and spin.
Issy Wong took her first Test wicket (Ryan Hiscott/Getty Images)
All four debutantes tried their luck with the ball, and there were maiden Test wickets for Bell – who picked up Lizelle Lee as well as Kapp – and Wong, who was unsurprisingly the fastest of England's seamers and accounted for Laura Wolvaardt, who was castled by a delivery that nipped back through the gate of South Africa's highly rated opener.
Kate Cross, the hosts' senior bowler following the retirements of Anya Shrubsole and Katherine Brunt, ended with the best figures of the seamers, picking up four wickets.
From where they found themselves, South Africa could be mightily satisfied with their day's work – Andrie Steyn's decision to leave a ball that cannoned into her off-stump had threatened to allow England the chance to run away with proceedings, especially when Wolvaardt, Lara Goodall and Lee all followed before the first session had come to an end. But their talismanic allrounder ensured a sense of relative parity heading into the second day.