Chief of the General Staff (abbreviated as CGS) is the most coveted position within the Pakistan Army after that of the Chief of the Army Staff (COAS). Although the COAS is the head of the land forces, the CGS is "the organizational lead on both intelligence and operations", hence being in charge of the Military Intelligence (MI) and Military Operations (MO) Directorates.[1] Since 1985, a three-star rank Lt. Gen. is appointed to the post.
The criteria for the positions of Chief of the Army Staff (COAS) and Chairman Joint Chiefs of Staff Committee (CJCSC) have a preference that the officer should have served as the Chief of General Staff. Of the last 13 four-star rank army generals, eight officers have served as the CGS. Of the five who hadn't, Pervez Musharraf and Ashfaq Parvez Kayani had served as Director General of Military Operations (DGMO), while Ehsan ul Haq had served as Director General of Military Intelligence (DGMI), all two-star postings under the CGS.
Historically, the Chief of General Staff, in addition to Commander X Corps have political significance when the army chief wanted to overthrow political leadership. The 1999 Pakistani coup d'état, which brought General Pervez Musharraf to power had active involvement of Lt Gen Aziz Khan, then CGS and Lt Gen Mahmud Ahmed, commander of the X Corps.
Therefore, the army chief essentially appoints his most trusted aides for these two postings before making a routine reshuffle. General Ziauddin Butt, who was nominated by Prime Minister Nawaz Sharif after retiring Pervez Musharraf, passed his first orders to appoint Lt Gen Muhammad Akram as CGS and Lt Gen Salim Haider as commander X Corps. But before this order could be conveyed to the rest of the army, Aziz and Mahmud took steps to reverse the order by overthrowing the government and thus essentially starting the 1999 coup.
1.^ Later promoted to lieutenant general in-office.
2.^ Later promoted to the post of a general.
3.^ Later promoted to Chairman Joint Chief of Staff Committee.