The Singapore Self-Propelled Howitzer 1 (SSPH 1) Primus is a self-propelled howitzer armed with a 155 mm howitzer. Developed jointly by the Singapore Armed Forces (SAF), Defence Science and Technology Agency (DSTA) and Singapore Technologies Kinetics (ST Kinetics), it was officially inducted to the Singapore Artillery in 2004. Primus is derived from the Artillery motto In Oriente Primus (Latin: "First in the East"). At the time of introduction in 2002, SSPH Primus was recognized as the world's lightest 155mm, 39 calibre tracked howitzer of its kind. Production history and development The idea for a self-propelled howitzer within the SAF was developed in the early 1990s, with the aim of providing better fire support to the armour brigades in the Combined Arms Divisions. This new weapon system would require the ability to keep pace with the high tempo of armoured operations, while providing the range, firepower and accuracy that the artillery is renowned for. The 155 mm self-propelled howitzer was seen as the obvious choice. The decision to develop the Primus was made after a market survey in 1995 and 1996 of some of the world's best self-propelled guns from the United States (M109 Paladin), United Kingdom (AS90 Braveheart), Japan (Type 75) and Russia (2S3M1) found them either too heavy or too wide for local terrain. Leveraging its experience with designing, developing and producing various towed artillery systems (the FH-88 and FH-2000) for the SAF, ST Kinetics, together with DSTA began the development of the Primus in earnest in 1996. By April 2000, the first working prototype was rolled out, using a vehicle chassis adapted from a United Defense armoured chassis (the Universal Combat Vehicle Platform; UCVP) which includes components from the US M109 Paladin howitzer, M2 Bradley IFV & M8-AGS. The next 2 years saw the system undergoing a series of comprehensive tests to ensure that the Primus was able to withstand the rigors required of it. As land in Singapore is scarce, firing tests were first done at the Waiouru Army Camp live-firing range in New Zealand as part of Exercise Thunder Warrior in February 2004. The guns have also participated in Exercise Wallaby at the Shoalwater Bay Training Area in Queensland, Australia. In September 2002, the Primus was officially certified to have met the SAF's criteria, and was formally adopted in the SAF. Since then, this Artillery platform is utilised by the 21st Battalion Singapore Artillery as their