One of the major draws of Seiko’s 6619 automatic line - like the overall exceptional 1967 Seiko 6619-8060 MACV-SOG Arabic dial automatic sport diver here, with vintage Waltham W.C.C. military compass, new-old stock (NOS) USMIL strap, and MACV-SOG patch - were their amazingly simplistic dials and hands.  These combine to form its single greatest aesthetic quality – symmetry.  But what else is significant about this Seiko 6619...
 
Ah yes – this is one of at least four Seiko divers procured by the U.S. Military Assistance Command Viet Nam – Studies and Observations Group (MACV-SOG) and issued to U.S. Special Forces during the conflict.  During the era these were made, Arabic numeral dial designs were rare and quite the departure from the norm.  It’s a safe assessment the Arabic numerals were one of the aspects MACV-SOG favored, and USMIL forces assigned to the secretive group were either issued these watches or instructed to purchase them at the PX before a covert ops tour.
 
A highly classified multi-service USMIL Special Operations unit, MACV-SOG conducted covert unconventional warfare operations prior to and during the Viet Nam War.  The unit conducted cross-border operations from Viet Nam into neighboring Laos, Cambodia, and North Viet Nam, with the USG infamously denying its existence until declassified in 1997.  SOG operations levied a high toll on North Vietnamese logistic supply lines and bases in Laos and Cambodia following the early 1968 Viet Cong Tet Offensive. 
 
But to operate in a non-attributable manner in these countries – where the USMIL wasn’t supposed to be – required atypical equipment.  Established in 1963 and principally run by Conrad “Ben” Baker, the USMIL's Okinawa, Japan-based Counter Insurgency Support Office’s (CISO) main mission was to issue standard and untraceable (read, sterile in appearance to offer a fig leaf of plausible deniability when USMIL forces were operating somewhere they weren’t supposed to be in the countries in and around Viet Nam) gear, clothing, and weapons to Special Forces in Vietnam, to include the USMIL’s MACV-SOG.  It would cease operation in 1973, following the US withdrawal.
 
The story of CISO and Ben Baker, these Seiko watches, and the work of SOG operatives is told by Frank Greco in his book, “Running Recon: A Photo Journey with SOG Special Ops Along the Ho Chi Minh Trail.”  The Seiko 5's ordered by Ben Baker have become much sought after in vintage military and Seiko collecting communities.  Want more on the MACV-SOG use of Seiko?  Read these two Watches of Espionage articles, here and here.
 
Per Greco’s tome and our additional in-depth research, SOG forces used four different Seiko references.  Some were CISO-issued beginning in circa 1968 and some preceded this time (so-called “Pre-CISO” watches) – the 6619, 6119-8100, 7005-8030, and the 6106-8100.  Of the four, the first iteration were the 6619 models, made available in two sequential styles,  the 8280 and then the 8060.  The 6119-8100 would subsequently replace the 6619, and be followed by the 7005-8030. 

This Seiko 6619 MACV-SOG comes on a NOS USMIL nylon strap, and with nylon strap, springbar tool, SOG patch, vintage Waltham W.C.C. military compass, and rugged travel case.