See how much you know about the year-end championships. (AP)

On Sunday, the 2018 WTA Finals will kick off in Singapore. There are a number of a familiar faces and a couple of newcomers that will battle in the almost 50-year-old event.

Last year, Caroline Wozniacki took home the title, and she's back this year, but anything goes with world No. 1 Simona Halep withdrawing and an on-fire Naomi Osaka making her debut. The field rounds out with Angelique Kerber, Karolina Pliskova, Kiki Bertens, Petra Kvitova, Elina Svitolina and Sloane Stephens. 

The WTA Finals have gone through many changes during its history; some things are well-known, others are more obscure. Now, see how much you know about the year-end championships: