Many thanks to this month's subscribers! TH03's enemy, fireball, and explosion code is in the very final stage of QA, but the blog post will still take a while. Life's been very slow lately. There'll be another exciting series of posts before then, though!

> Stumble over another MIDI sequencer that automatically decodes GS SysEx > OTAMA98 by MISO > Still works on Windows 11 > No bloat, no lengthy "analysis" phase, no hardware dongles, no bullshit > Even does XG! Though not as detailed… > …and GS support stops at SC-88, no Pro 😩

And yes, the extend glitch happens for the same reason once your score is ≥20 million and if that one segment lies at 0x3E?? (P1) or 0x2E?? (P2). And 0x2EF4 is exactly where the 2021 Ultimate Collection happens to place that segment if you play on anything other than DOSBox-X.

Found the cause of TH03's score reduction glitch! youtu.be/JltuH7nAO4Y?... It occurs on certain PC-98 setups if you destroy a fireball with anything that isn't an explosion on a frame where you previously got a VSync/PMD interrupt within a specific window of CPU instructions.

github.com/nmlgc/rec98.... [💰] Confirm T0414 Ember2528 is still with us, and once again bought all remaining capacity from the store! €154 towards his current long-term plan of Shuusou Gyoku replays followed by TH03 decompilation and porting. Thank you so much!

Many thanks to this month's subscribers! (As in, December's.) The current plan: 1) Lots of TH03 gameplay code (≥8.65% of MAIN.EXE) 2) Headless Shuusou Gyoku for automated replay validation 3) Probably a bit of TH02? Unless we've got clearer funding for something else by then.

🚚 Delivered a complete decompilation of and research into TH03's bullet system! A minor iteration on TH02's rather decent system, but definitely the point where bullet systems in PC-98 Touhou took a turn for the worse. 🐞 1 bug 💣 1 landmine 🎺 4 quirks 🪨 33 pieces of bloat

What was this delay. In exchange, I've got an unexpectedly long >6,500-word blog post about TH03's bullet system and a certain other issue, coming your way very soon. Fingers crossed I'll get it out while it's still 2025 in UTC.

TH03 Chiyuri has a very rare quirk where 1 or 2 bullets are randomly missing from the 48-ring pattern in her Level 1 or 2 Boss Attack if she launches it multiple times in a row. Explaining the cause certainly contributed to the massive delay of the upcoming blog post…

How to disqualify yourself for self-hosted archival storage: • Effectively prevent backdating by prioritizing crawl date in the AppView everyone uses • Importer insists on JPEG, and ignores tweets if you try PNG 🤮 Onto the Fediverse, then. activitypub.nmlgc.net/@rec98

The border between the two playfields in TH03 is not just visual, but an actual part of the simulated game world. Every transferred pellet or fireball physically travels through these 32 pixels before it appears on the other playfield.

Many thanks to this month's subscribers! Once again, the scope has expanded to include TH03's bullet and combo systems. Bullets are only missing one detail and will get a dedicated blogpost very soon. We're going to see at least 5 pushes and 10% more RE for MAIN.EXE in December.

TH03 decompilation will progress *so quickly* once I get the basic gameplay systems done. ZUN really did implement most of the character-specific systems by copy-pasting the same code 9 times with minor variations. That means ~3× the decompilation speed of TH01 at its fastest.

Many thanks to this month's subscribers! The next delivery will fully cover TH03's enemy, fireball, and explosion systems. No netplay this year though, Shuusou Gyoku replays have shaped up to be too complicated. (It might also make sense to have TH03 replays before netplay.)

While I'm working on TH03, let's design the replay format I'll use for Shuusou Gyoku and PC-98 Touhou! If there's anything you've ever wanted to see in a replay format, now's your chance to influence the design and feature set. github.com/nmlgc/ssg/is...

A landmark Neko Project 21/W release happened yesterday! SimK has finally murdered the horrible abomination that was the secondary set of ASCII glyphs in Neko Project's old auto-generated replacement for the PC-98 ROM font. twitter.com/simk98l/stat...

🚚 Delivered the planned Shuusou Gyoku maintenance release. SDL 3 is now a hard dependency (even on Windows 98!), the SDL 2 code path is gone, and the Linux version now compiles with GCC ≥15. No new features, but a few bugfixes and speedups surrounding screenshots and fonts.

Many thanks to this month's subscribers! The current plan for the rest of the year: 1) Shuusou Gyoku maintenance (will quickly free up some budget) 2) TH03 RE 3) Better replays for Shuusou Gyoku 4) TH03 netplay (would be nice to get it done by the end of the year)

🚚 Released the first version of the TH03 Anniversary Edition together with the first debloated builds of all five games! Primarily reduces lag in menus and cutscenes as a first step towards portability, but also comes with a single new feature. Download: github.com/nmlgc/ReC98/...

The end is near! >9,800 words, and probably the last big blog post for this year. I wanna code again! Out within the next few hours…

$ git diff --stat debloated~193 debloated […] 259 files changed, 4145 insertions(+), 8099 deletions(-) ~4,000 lines of ad-hoc PC-98-native graphics code, bloat, landmines, bloat- and landmine-documenting comments, and binary-specific inconsistencies removed from game code 🎉

🚚 Part 3 is out, bringing five disconnected and small decompilations and actually shifting the percentages on the front page for a change! 🐞 5 bugs 💣 3 landmines 🎺 2 quirks 🪨 24 pieces of bloat

> Next post is about five small and disconnected RE tasks > Try to write five short paragraphs with bullet points in the style of touhou-memories > Still end up with over 2,000 words Coming to you within the next few hours…

Part 2 of my 4-part 2025 PC-98 Touhou portability series is out! This one is also our second deep dive into PC-98 blitting performance with two new benchmarks, and also looks at the two libraries that ZUN used to load PI images. Not a lot of Touhou-specific content in this one.

Second part is in proofreading. Over 9,300 words about PC-98 blitting and the .PI format, coming to you within the next few hours…

📝 Wrote a post about the various strategies of porting PC-98 Touhou to modern platforms! Also clears up common misconceptions about the performance of the PC-98 originals. This one is required reading for anyone who wants to see these games ported. Link: rec98.nmlgc.net/blog/2025-09...

Trying something new this time! The next release touches on so many topics that one blog post would have been way too intense for everyone. So I'm splitting it up into 4 posts, with each focusing on a different topic. First part (~8,000 words) coming within the next few hours…

Many thanks to this month's subscribers! Code is done escalating, and now it's the blog post's turn. Got >13,000 words now and it's still missing lots of content… I'll be so relieved once I get to spend the rest of the year on TH03 and Shuusou Gyoku with no more distractions.

Here's all the ZUN quirks, bugs, landmines, and bloat from previously RE'd code that I missed or got wrong in previous pushes and fixed for the upcoming ones. Reverse-engineering is hard.

Testing completed.

Here's a funny script bug in TH04's Good Ending for Reimu A that I just stumbled over. ",4魔理沙"?! 🎺 (Third-party clip from 2013 for proof: www.youtube.com/clip/UgkxUo6...)

⚠️ Another Shuusou Gyoku Extra Stage replay desync bug? This time though, it's the actual catastrophic kind: An accidental fork of Marisa's gameplay that might invalidate replays recorded on any ReC98 build from the last 10 months, now that I've restored the original behavior.

Many thanks to this month's subscribers! 384 commits across 10 pushes coming your way soon… (Hopefully)

Alright, got to where I wanted to be. Merged the OP and MAINL/MAINE binaries of TH02-TH05 into a single one that's smaller than either of the original ones. No compression. And yes, they spawn missing drivers as needed. No GAME.BAT necessary. Also works with any PMD/MMD version.

Yup, we're going there again.

TH05's title screen crossfading effect is probably the most visible case of lag reduction in the upcoming ReC98 builds. Here's how the original game looks on Neko Project 21/W with a 66 MHz CPU, which is the usual recommended clock speed for emulating PC-98 Touhou:

The upcoming ReC98 builds will not only come with reduced lag in TH02-TH05 menus and cutscenes, but also bring a highly important quality-of-life feature to TH03: 🥁 Quitting out of the VS Start menu without going through the Select screen. 🙌

Fun fact: A TH04/TH05 GENSOU.SCR file that consists entirely of 00 bytes is valid and passes the game's checksum validation. Here's how such a file looks like in the High Score viewer, after the game spent way too much time rendering garbage data:

Let's check the general community sentiment toward a crucial PC-98 Touhou portability question! This is how screen fade effects look in the original games. They work by manipulating the 16-color hardware palette within its 12-bit RGB444 color space.

Players have reported several score bugs in TH03 I've yet to look into, but here's an obscure one I just found. ZUN didn't look at the last digit when sorting new scores into the High Score list 🎺 Identical scores with different credit counts always appear in insertion order.

Many thanks to this month's subscribers! Not posting a lot here only means I'm working on something huge. Up to 261 commits now, more than half of them on master, and nearing feature completion. Releasing mid-July, probably? Still got lots of testing and explaining to do…

When you realize that the PC-98 has 768×4 bytes of offscreen VRAM instead of just the 80×4 bytes that ZUN used for this effect:

Wait, BERO's PiLoad library (used in TH01) is more than 2× as fast as master.lib's PI functions (used in TH02 and later)? Yup. A masterclass in x86 optimization. 🙇 ZUN may have just switched because PiLoad only loads to VRAM and not memory, but that feature is quickly added.

Many thanks to this month's subscribers! Currently deeply submerged in portability and code cleanup issues. Let's hope I resurface soon…

It sure takes a bit of effort to fix all the screen tearing landmines in PC-98 Touhou while still maintaining the exact original frame timing. The resulting code is often not natural at all.

Fixed two replay bugs in the ReC98 Shuusou Gyoku build: • Extra Stage replays recorded in ≥P0295 were highly likely to desync • ≥P0217 saved twice as many replay frames as necessary Watching an affected replay in the new build will repair the desync and recompress the file.

🚚 TH03's OP.EXE has been fully decompiled, completing the last missing main menu of PC-98 Touhou! This one comes with a few unused labels, and demos that point us to unexpected additional replay value?👀 🐞 1 bug 💣 2 landmines 🎺 1 quirk 🪨 35 pieces of bloat

This time, I've got 2,900 words about TH03's main menu, a certain unexpected gameplay detail that will make netplay even more interesting, and the usual plans for the immediate future. Coming to you in the next few hours.

Many thanks to this month's subscribers! I'd like to pause Shuusou Gyoku until August, so we'll have lots of netplay-focused TH03 progress in the next few months. But there's enough funding to occasionally work on specific small things in any of the other 4 games if requested.

github.com/nmlgc/rec98.... [💰] Confirm T0372 €5 from Koa towards reconstructing the original installers of the PC-98 Touhou games? That'll probably capture a good chunk of the Anything funding at some point. Thank you!