IGS built the PolyGameMaster in 1997 to out-Neo-Geo the Neo Geo—a faster processor, sprites that could zoom, and a cartridge slot for a library that's still running in Taiwanese arcades today. Then, for a couple of strange and wonderful years, it became the board a few of Cave's sharpest shoot-'em-ups called home.
By 1997 the Neo Geo was the aristocrat of cartridge arcade hardware: swappable games, lavish sprites, a run that already stretched most of a decade. So it took some nerve for a Taiwanese company to look at SNK's machine and decide it could be beaten at its own game. That company was IGS—International Games System—the board was the PolyGameMaster, and the pitch was blunt: everything the Neo Geo does, with more muscle behind it.
Out-muscling the Neo Geo
The spec sheet reads like a Neo Geo with the governor removed. Where SNK's board ran a 68000 at around 12 MHz, the PGM clocks the same chip at a full 20 MHz, backed by a Z80 and an ICS2115 sound chip good for 32 channels of PCM audio. Its sprites don't just shrink the way the Neo Geo's do—they zoom, scaling up as well as down—and it lays a background tilemap underneath them for real depth. Games shipped as cartridges built from a pair of PCBs, dropped into any JAMMA cabinet, with an ARM chip aboard that started as a security guard and didn't stay one: on later cartridges the 24 MHz ARM7 computes the sprite positions for the Cave shooters, and on the final games it runs most of the gameplay logic itself. Core author Martin Donlon has noted that a late PGM cartridge alone packs more processing power than most whole arcade systems of the eighties. It even pushed to four players on eight-way sticks. It was, as one writer neatly put it, an even more Neo Geo.
Knights of Valour and the home crowd
For most of its life the PGM wasn't a shmup board at all—it was a brawler board, and a wildly successful one in exactly the market it was built for. The signature is Knights of Valour, a Romance of the Three Kingdoms beat-'em-up that arrived in 1999, spun into a series of nearly a dozen entries, and—this is the part that gets me—still turns up in arcades across Taiwan and mainland China today, decades later. Around it sits the rest of the IGS catalog: the early hit Oriental Legend, later fighters like Martial Masters, big-sprite four-player scrums made for a coin-op scene the Western retro crowd mostly never saw. That library is the PGM's real legacy. The shmups are the plot twist.
When Cave came to stay
Here's the twist. In the early 2000s, Cave—the Japanese studio whose name is synonymous with bullet-hell—put three of its games on this Taiwanese brawler board: DoDonPachi DaiOuJou (2002), Ketsui (2003), and Espgaluda (2003). DaiOuJou even shipped with a modified BIOS—the standard PGM startup screens hacked out—and Ketsui and Espgaluda went further, absorbing the BIOS into the game program entirely. For a couple of years, some of the most worshipped curtain-fire shooters ever made ran on hardware designed to sell four-player scrollers in Taipei.
It's worth being precise about what that was and wasn't. PGM was a rental, not a home: in 2004 Cave moved to its own board, the CV1000, launched it with Mushihimesama, and ran its arcade lineup from there—almost without exception: in 2010 Cave quietly developed one last PGM-family title, DoDonPachi DaiOuJou Tamashi, published by IGS on the PGM2 for the Chinese market. So the PGM's shmup era was a brief early-2000s window, not the whole story—but what a window. (One fun wrinkle for the record: DoDonPachi II: Bee Storm, also on PGM, wasn't Cave at all—it was IGS's own in-house sequel to Cave's series, which is exactly as odd as it sounds.)
Where to actually play it
The map splits neatly. The IGS brawlers are the easy half now—the company put out a Classic Arcade Collection (Switch, with a PC release listed for 2026) with Knights of Valour and friends, so those are a click away. The Cave PGM shmups are the hard half: original boards are collector-priced and the conversions are their own rabbit hole.
Which is exactly where the FPGA earns its keep. The MiSTer has an IGS PGM core by Martin Donlon, known as wickerwaka, so the entire library—brawlers and bullet-hell alike—runs on the same little board that already lives on my bench. If you've read my MiSTer explainer, you know the pitch: one FPGA, a shelf of arcade boards it can become. PGM is one of the more satisfying ones to add, precisely because so little of it ever left Asia on real hardware.
The PolyGameMaster has a split personality: a workhorse that kept Asian arcades stocked with brawlers for a decade, and—for one brief window—an unlikely vault for some of Japan's finest shooters. It's one of two great arcade boards that made their name entirely outside the Neo Geo's shadow. The other belongs to Psikyo—and that's where this goes next.
Frequently asked
What is the PolyGameMaster?
The PolyGameMaster (PGM) is an arcade board IGS—International Games System—built in 1997 to out-muscle the Neo Geo, with a 68000 clocked at 20 MHz, a Z80, an ICS2115 sound chip, and sprites that could zoom.
What was the PolyGameMaster's most successful game?
For most of its life it was a brawler board, and its signature was Knights of Valour, a Romance of the Three Kingdoms beat-'em-up from 1999 that spun into nearly a dozen entries.
Which Cave shooters ran on the PGM?
In the early 2000s Cave put DoDonPachi DaiOuJou (2002), Ketsui (2003), and Espgaluda (2003) on the board before moving to its own CV1000 board in 2004.
Was DoDonPachi II: Bee Storm made by Cave?
No—DoDonPachi II: Bee Storm, also on the PGM, was IGS's own in-house sequel to Cave's series, as its IGS copyright line shows.
Further reading
- PolyGame Master—Wikipedia—the board, its hardware, and its full game list.
- The IGS PolyGameMaster: An Even More Neo Geo? (nicole.express)—a hardware teardown and the source of the "even more Neo Geo" framing.
- Interview: Martin Donlon (wickerwaka) on the MiSTer PGM core (Artemio Urbina, 2026)—the core author on the board's secrets, from the ICS sound chip's Gravis Ultrasound kinship to the ARM7 that quietly runs the show.
- Knights of Valour—Wikipedia—the PGM's signature series.
- Arcade-IGSPGM_MiSTer (the FPGA core)—wickerwaka's IGS PGM core for MiSTer.
- What is MiSTer? The FPGA that plays every Atari I don't own (Bench Notes)—how one board becomes many.
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