Gambians will cast their votes on Saturday using a unique voting system, marbles dropped in each candidate’s ballot drum, in a tightly fought presidential election that will test stability and democratic progress in the tiny West African nation.

Nearly one million people out of a 2.5 million population are registered to vote in mainland Africa’s smallest country. Turnout is expected to be high, according to election officials.

“The number of people registered is far more than the previous election,” said Mamadou A. Barry, a returning officer at the Independent Electoral Commission (IEC).

According to Barry, Gambians understood the process of using glass marbles to vote. The system was introduced in the 1960s to avoid spoilt ballots in a nation with a high illiteracy rate.

“Each voter gets a marble,” he said. “I think it is transparent and fair.”

Results are expected by Sunday under the simple majority system. It is Gambia’s first democratic election since former President Yahya Jammeh was voted out of office in 2016.