Use of biometric and difficult process of using manual killed stronghold rigging. The only strongholds in the last election was Kalenjin and Luo land.
GEMA was not anyone stronghold - both camps had very serious support across the board.
What remain is remote areas rigging - where prov administration/nis/party - still collude to rig out the final tally.
Uhuru spend a lot of resource on chiefs and NIS to rig Ruto.
Obviously in Mt kenya - my brother is DC - they attempted - but Ruto crew were ahead - and chiefs were harrassed and outed.
What helped Ruto through all the rigging was his counter-intelligence - he knew their plans before.
Rigging attempt went on until the last minute - as you know bomas sending of KDF/Police to intimidate chebukati after bribery and kidnapping and name it.
He did try but didnt go as expected in Mt Kenya area because it was Rutos stronghold . Its hard to to rig your opponents stronghold because the supporters are vigilant. You can rig your strongholds and battleground which Raila did in both 2007 and 2008 .
If Mt Kenya had become a battle ground as Uhuru and Raila wanted it to be Ruto would be opposition leader as we speak .