flight testing of the prototypes was reportedly around half way complete, having accumulated a combined 400 flight hours during testing, further tests focused on flight validation, operational evaluation, and mission equipment functionality. These four prototype aircraft were all later remanufactured to conform to production standards and redelivered under new serial numbers to the JGSDF. In June 1998, in response to the finalising of a production contract and an initial order for two OH-1s having been placed earlier that year, the manufacture of production OH-1s formally commenced; By the late 1990s, the JGSDF had announced that it had planned to procure between 150 and 250 OH-Xs to meet its requirements. This figure was significantly fewer than the 297 OH-6Ds that were in active service by March 1995, and there were repeated concerns that numbers could be further curtailed as a result of the impact of defense budget cuts. Procurement, and thus production, of the OH-1 was of a slow pace; each year, only a handful of rotorcraft would normally be purchased, such as a pair of OH-1s being the only units procured in 2004. By 2013, production of the OH-1 was reportedly as presumed to have been terminated. Further development During the 1990s, the JGSDF was interested in procuring a new attack helicopter during the following decade, seeking to replace the Fuji-built Bell AH-1 Cobra fleet. Amongst the proposals produced by Japanese industries was a derivative of the OH-1, tentatively designated as the AH-2. In 1999, it was revealed that the JGSDF was actively studying the modification of the OH-1 into an attack helicopter suitable to their requirements. The OH-1 had been intentionally designed with additional margin to accommodate such growth of scope, the main limiting factors being its transmission and engines. The AH-2 proposal would have involved installing uprated engines and the addition of new unspecified armaments for anti-tank combat missions; Boeing in particular was dismissive of the value of the proposed rotorcraft, claiming that it "cannot fulfill the attack requirement". Kawasaki's proposal was ultimately rejected in favour of a locally-built variant of the Boeing AH-64 Apache. In 2005, Kawasaki proposed the development of a utility-orientated derivative of the OH-1 in response to the fledgling UH-X programme, which intended to replace the JGSDF's outdated fleet of Fuji-built Bell UH-1J Iroquois helicopters. This variant, which would have used the OH-1 as a base, would have featured a new cabin, avionics, transmission