the 480-line mode of VGA and a processor as fast as the 80386 would realize his idea, but they were expensive hardwares as of 1987. In this era, Toshiba released the J-3100 laptop computer, and Microsoft introduced the AX architecture. IBM Japan didn't join in the AX consortium. His boss, Tsutomu Maruyama , thought IBM's headquarters wouldn't allow to adopt the AX because they requested IBM Japan to use the same standard as worldwide IBM offices used. In October 1987, IBM Japan released the PS/55 Model 5535 which was a proprietary laptop using a special version of DOS. It was more expensive than the J-3100 because its LCD display used a non-standard 720×512 resolution. Hatori thought IBM needed to shift their own proprietary PC to IBM PC compatibles. Maruyama and Nobuo Mii thought Japan's closed PC market needed to be changed and this attempt couldn't be done by IBM alone. In summer of 1989, they decided to carry out the development of DOS/V, disclose the architecture of PS/55, and found the PC Open Architecture Developers' Group (OADG). The DOS/V development team designed the DOS/V to be simple for better scalability and compatibility with original PC DOS. They had difficulty reducing text drawing time. "A stopwatch was a necessity for DOS/V development", Hatori said. IBM Japan announced the first version of DOS/V, IBM DOS J4.0/V, on 11 October 1990, and shipped out in November 1990. At the same time, IBM Japan released the PS/55 Model 5535-S, a laptop computer with VGA resolution. The announcement letter stated DOS/V was designed for low-end desktops and laptops of PS/55, but users reported on BBS that they could run DOS/V on IBM PC clones. The development team unofficially confirmed these comments, and modified incompatibilities of DOS/V. It was a secret inside the company because it would prevent sales of PS/55 and meet with opposition. Hatori said, Maruyama and Mii had to convince IBM's branches to agree with the plan. In the beginning of December 1990, Maruyama went to IBM's Management Committee, and presented his plan "The low-end PC strategy in Japan". At the committee, a topic usually took 15 minutes, but his topic took an hour. The plan was finally approved by John Akers. After the committee, Susumu Furukawa, a president of Microsoft Japan, could make an appointment with IBM Japan to share the source code of DOS/V. On 20 December 1990, IBM Japan announced