A total of 26,597 teachers are racing against time to complete marking this year's Kenya Certificate of Secondary Education (KCSE) examination.
A majority of the teachers are expected to complete marking by Thursday, before departing from the 20 stations in Nairobi and its environs on Friday.
By Tuesday, a number of examiners were already done with the exercise and were busy compiling marks to be uploaded into the system.
The end of marking the scripts will set the stage for the release of the results next week by Education Cabinet Secretary George Magoha.
Prof Magoha promised Kenyans that the results will be out before Christmas.
"Those marking the examination will use the conveyor-belt system in that the examiners cannot mark more than one question," said the CS at the Kenya High School two weeks ago when the exams ended.
The marking of the examinations started on November 28, a day after the last paper was sat.
This year's marking was characterised by protests by examiners over poor pay and poor working conditions.
Marking at Upper Hill, Nairobi, and Machakos Girls was suspended for some hours due to protests that forced the Kenya National Examinations Council (Knec) to intervene.
ICT experts at the centres are tasked with keying in the marks for easy processing.
The examinations, which started on November 4, ended on November 27 with a total of 21 cases of exam malpractices being reported.
Prof Magoha also said 90 phones were confiscated from candidates.
He disclosed that 300 schools had been put under watch following reports of planned cheating.
He identified Nairobi, Kisii, Migori, Homa Bay, Wajir and Garissa as some of the counties that recorded cases of examination irregularities.
This year, 699,745 candidates sat for the KCSE exams.