If you're a Touhou Project fan, you might obviously know the PC-98 games. The NEC PC-98 was one of the most memorable home computers from Japan in the 1980s and 1990s. Today, the PC-98 sound chip is often recognizable by Touhou fans.
The Challenger
The PC-98 uses a YM2203 (OPN) or YM2608 (OPNA) with both FM and SSG channels. The YM2203 has six voices, while the YM2608 has 16 voices. You may think the YM2608's better, but no. See the next section for details.
FM Synthesis: The YM2203 has three FM channels, while the YM2608 has six FM channels. The FM sound used is similar to the YM2612 used in the Sega Genesis. An expansion chip similar to the YM2608's chip is the YM2413, which was used in Konami's VRC7 chip in the Nintendo Entertainment System. The external links at the end of this document have the instruments that ZUN made, while the TFM Music Maker, which is a tracker based on the YM2203, can let you make your own instruments.
SSG: The SSG can only produce square waves similar to the YM2149, which was used in the Sunsoft 5B in the Nintendo Entertainment System. ZUN used the third SSG for the drums.
ADPCM: The ADPCM is a PCM channel that can let you import ADPCM sampled sounds between 2,000 - 16,000 Hz which was used in the Super Nintendo, such as an orchestral hit or any other drums. This voice is not available in the YM2203.
Rhythm Sound Source: The Rhythm Sound Source, called RHY in Hoot, is a six-channel drum system that has all the major drum sounds you'd hear in a drum set, such as bass and snare drum, and the open/closed high hats. When I do my song covers, I use one channel for the hats and cymbals and another for the bass drum and snares.
Examples
Here are some examples of PC-98 music I made:
This part is unavailable to be recreated due to file preservation limitations on the Wayback Machine
Recognizing samples by filename
When you download the sample collection, it will have almost every sample ZUN used. FM samples will have "f" at the beginning. SSG samples will have "s" at the beginning, and the SSG drum samples will have "p" at the beginning.