The event at Randpark also marks the start of The Open Qualifying Series, with three spots up for grabs in next year’s 150th edition at St Andrews.
Introduced in 2014, The Open Qualifying Series, coupled with Final Qualifying, will offer a minimum of 46 spots for the 2022 edition of the game’s oldest major.
Four home players - Dean Burmester, Dylan Frittelli, Justin Harding and Shaun Norris - are already exempt for the Claret Jug event next July.
But, for the others in this week’s field on the Firethorn Course, including Scottish quartet Richie Ramsay, David Drysdale, Craig Howie and Liam Johnston, it’s an exciting opportunity.
As things stand, 1999 champion Paul Lawrie and Bob MacIntyre, who finished in the top 10 this year, as the sole Scots on the exempt list, with the full categories due to be released shortly by the R&A.
The St Andrews-based body is also currently working with the leading pro tours to finalise the other events to be part of Qualifying Series on this occasion.
Professionals and amateurs will also be able to reach The Open via Regional and Final Qualifying, on Monday, 20 June and Tuesday, 28 June respectively.
World No 76 Burmester is the highest-ranked player in the Joburg Open field, which also includes 2018 Scottish Open winner Brandon Stone and Jovan Rebula, who won the 2018 Amateur Championship at Royal Aberdeen.
Meanwhile, 10 spots in next year’s AIG Women’s Open at Muirfield will be filled at the end of this week’s final event of the LET season in Spain.
The coveted berths will go to the top 10 players in the Race to Costa del Sol after the Andalucia Costa del Sol Open de Espana at Los Naranjos, near Marbella.
Kylie Henry, who sits 14th in the standings, is an absentee as Kelsey MacDonald (40th), Michele Thomson (53rd), Alison Muirhead (83rd) and Catriona Matthew (106th) all bid to sign off the season in style.