the MU-2F were sold. Beginning with the MU-2G, the fuselage was stretched. The MU-2M, of which only 28 were built, is regarded as the toughest and most desired of all short-bodied MU-2s, especially with a −10 engine conversion. It had a short fuselage and the same engines as the MU-2K and stretched MU-2J, and had an increase in cabin pressurization to 6.0 psi; it was followed by the MU-2P, which had newer, four-blade propellers. The final short-fuselage MU-2s produced were known as Solitaires and were fitted with Garrett TPE331-10-501M engines. The first significant change to the airframe came with the stretched MU-2G, first flying 10 January 1969, which featured a 1.91 m (6 ft 3 in) longer fuselage than earlier models; 46 were built before being succeeded by the more powerful MU-2J (108 constructed). The MU-2L (29 built) was a higher-gross-weight variant, followed by the MU-2N (39 built) with uprated engines and four-blade propellers. The final stretched-fuselage MU-2 was named the Marquise, and like the Solitaire, used TPE331 engines. Operational history Military service Japan The Japan Self-Defense Forces are the only military operators to have flown the MU-2 in front-line service. Ground Self-Defense Force The four C-model aircraft built, in addition to 16 MU-2Ks, entered service with the Japan Ground Self-Defense Force (JGSDF) with the designation LR-1; they were used as liaison and photo reconnaissance aircraft. They were retired in 2016. A number of them have been placed as gate guardians at JGSDF bases. Air Self-Defense Force 29 MU-2Es were purchased by the Japan Air Self-Defense Force as search-and-rescue aircraft and designated MU-2S. Additional equipment consisted of a "thimble" nose radome, increased fuel capacity, bulged observation windows, and a sliding door for dropping rafts. They were replaced in 2008 by the British Aerospace U-125A. Some have been preserved. Argentina Four civilian MU-2 (LV-MCV, LV-MOP, LV-OAN and LV-ODZ) were acquired by the Argentine Air Force during the Falkland War. These Mitsubishi were unarmed, but used during combat operations by the Escuadrón Fénix as pathfinders, reconnaissance and comm-relay planes. Among their missions were flying as guiding planes to the IA-58 Pucará replacements required after losses on the raid on Pebble Island. New Zealand In late 2009 the Royal New Zealand Air Force (RNZAF) took delivery of four Mitsubishi MU-2F fixed-wing training aircraft from the United States for use as training aids. In New Zealand service they are known as the Mitsubishi MU-2