The Kenya Certificate of Secondary Education examination kicks off Monday under tough, new guidelines.
The Ministry of Education, for instance, has said apart from examination officials, candidates and security officers, only headteachers and their deputies would be allowed in school compounds.
Deputy county commissioners and sub-county directors of education are not allowed to open containers housing the examination materials before 6am.
Every container, kept at the sub-county headquarters countrywide, has a double locking system.
Candidates rehearsed for the examination on Friday after concluding their practical tests, which started on October 23 and ended on November 2.
The practical papers already assessed are French (oral and Braille), German (oral), Arabic (oral), Kenya Sign Language (practical skills), music, building and construction and home science.
The 615,772 candidates in 9,350 centres will sit the mathematics alternative 'A' examination at 8am followed by chemistry at 11.30am.
Education Cabinet Secretary Fred Matiang'i last week said he expected schools to provide a conducive environment for learners during the month-long examination period.
Dr Matiang'i said Monday's tests would be administered with the same zeal as the Kenya Certificate of Primary Education examination, which ended on Thursday last week.
The Nation teams found students in various schools rehearsing for the examination on Friday.
At Jamhuri High School in Starehe Constituency, Nairobi, the principal, Mr Fred Awour, said 147 candidates were ready for the tests. Another 334 private candidates will sit the papers at the school, which was recommended by the sub-county director of education.
Already, supervisors and invigilators for this year's annual national tests have been briefed on the exercise by the Kenya National Examinations Council in Nairobi.
Some 21,828 examiners will oversee the one-month test season.
A multi-sectoral examination monitoring group will be visiting different parts of the country as the tests proceed.
Knec chairman George Magoha told the Nation that the examination would be credible.
"No paper will be leaked," Prof Magoha said.
The Form Four national tests have become synonymous with rampant cheating in recent years, with papers available to students hours -- sometimes days -- in advance, and widely circulated on encrypted social media platforms.
At the Coast, examination materials were delivered to centres in Kinango, Kwale County yesterday after a delay caused by a downpour.
There were delays during the KCPE examination in the same area last week because of the rains, which rendered most roads impassable.
Fifty-two inmates in different prisons at the Coast will sit for the tests.
Regional Police Commandant Larry Kieng yesterday said security had been improved.
More police officers have also been deployed to terror-prone counties of Lamu and Tana River ahead of the examination.
Similarly, in the Rift Valley, more police officers have been deployed to banditry-prone areas.
Regional Coordinator Wanyama Musiambo said a standby reinforcement team would be dispatched to examination centres should need arise.
Baringo County Commissioner Peter Okwanyo said normality had been restored in the rustling-prone Baringo South and North sub-counties.
More than 12 Administration Police officers have been deployed to every school in the two sub-counties, while General Service Unit camps have been set up in Kapindasum, Kasiela, Arabal, Kagir and Chemorong'ion locations.
In Laikipia, Kenya Union of Post-Primary Education Teachers county executive secretary Ndung'u Wangenye urged tutors and to avoid examination irregularities.
"The union will not protect or defend teachers involved in examination cheating and other malpractices," the Kuppet boss told the press.
Meru County Commissioner Wilfred Nyagwanga said examination materials for 10 sub-counties would be stored in one container. However, Buuri Sub-County would have two.
Nyanza Regional Education Co-ordinator Richard Chepkwai said his office had taken adequate steps to ensure the national examination went on without any hitches.
"We were a bit worried that some areas could be challenging in terms of accessibility but we want to assure students, teachers and parents that everything is okay. We are prepared for any emergency," he told the Nation on Sunday.
In Kakamega, County Director of Education Fred Kiiru said everybody was set for the examination.
The county has 28,367 candidates in 416 centres.
Principal Secretary for Broadcasting and Telecommunications Sammy Itemere is expected to oversee the start of the examination in the county at Musingu High School, Kakamega South Sub-County.
At Cardinal Otunga High School in Kisii County, candidates were busy revising for the examination on Sunday.
School head Zachary Nyariki said the institution had acquired special desks to be used by the candidates during the examination instead of the usual lockers to prevent cheating.
Siaya County Education Director Kituyi Masibo said the safety of students in the 234 examination centres was a priority.
"We have taken into account all security measures as a way of ensuring that the candidates are safe," Mr Masibo said.
Reported by Joseph Wangui, Manase Otsialo, Alex Njeru, Wycliff Kipsang, Florah Koech, Barnabas Bii, Victor Raballa, Benson Amadala, Derick Luvega, Geoffrey Rono, Vivere Nandiemo, Elgar Machuka, Nelcon Odhiambo and Mohamed Ahmed.