Why does Jinteki want to defend Archives?

A couple good reasons come to mind:

• Jinteki: Restoring humanity wants to get their sweet drip credits
• Kakurenbo works a lot better if there are facedown cards in archives at the start of your turn. Usually the question for the runner is, did you use Kakurenbo to replay a trap out of Archives, or did you play something like an agenda from hand. If archives was revealed before you play Kakurenbo, then after you play Kakurenbo, the runner can run Archives and if it looks exactly the same, then they know you played something from hand.
• In Midnight Sun, we have new cards like Moon Pool and Regenesis, enabling Archives focused shenanigans described in a blog post by Doomrat
• Counterplay to Security Testing builds, Sneakdoor Beta, Sabotage focused runners, etc.

How do popular icebreakers fare?

• Bukhgalter breaks it for 2, including the discount. This is the same cost as Drafter, which is also rezzed for 3. I posit that Drafter is quite playable in the current meta.
• Afterimage needs 1 normal and 1 stealth credit, or two leech counters and a normal credit, so this is fairly taxing to that icebreaker
• Carmen breaks it for 3
• Mimic cannot break it unless the runner can reduce the strength by 1.
• Echelon likely breaks it for 4, (but only 1 if you have 4 icebreakers installed)

What alternatives stand out?

• Saisentan (probably) does more damage to the runner if they face-check without a killer. But it costs 5 to rez rather than 3, and is broken for the same or less with all of the above killers. On the flip side, Saisentan resists Boomerang and Botulus better than this ice.
• Karuna costs one more to rez, has one more sub and one less strength. A face-check without a killer is usually only going to do 2 net damage. Karuna is a bit weaker vs. Afterimage and Mimic. This ice is not often played in the current meta, because it usually is pretty low impact -- the runner either runs with their killer, or hits it with boomerang before running, and then it costs 4 to rez and probably does nothing for the rest of the game. In most cases you'd rather have Saisentan, because if they facecheck it it can kill them outright, and even if they hit it with Boomerang, you still probably do 1 or 2 net damage.

This ice is a lot closer to Karuna than Saisentan, and the same arguments against Karuna applies to this ice -- boomerang and botulus completely break it, and most runners won't blindly face-check this. But the difference is that it is bit more efficient than Karuna -- it's still 2-ish to break and it's only 3 to rez rather than 4. So we're reaching towards Drafter levels of efficiency in a faction that is usually pretty poor.

In Jinteki: Personal Evolution, it's possible that Anemone is an all around better choice than this for defending Archives.

• Anemone is only two and a card to rez. Anemone does 3 net damage if the sub fires, but does 2 guaranteed net damage even if the sub is broken -- even if the runner played Inside Job and bypassed the ice.
• Because when you rez Anemone you pitch a card from your hand into Archives, it is possible that the corp pitches Sting! into archives when Anemone is rezzed. If there are a bunch of other facedown cards in Archives, then it's possible that the runner can be flatlined. So when Anemone is rezzed, it is likely that the runner actually jacks out. This is very tempo positive -- you paid two and a card, did two net damage, and the runner jacked out, abandoning their click. They probably spend the rest of their turn drawing up and don't actually run Archives until the next turn.
• This probably isn't what happens with Bathynomus -- they probably break it for 2ish, take no net damage, and complete their run.
• This argument doesn't apply if the runner is using Sneakdoor Beta, in that case you'd rather have Bathynomus.

Jinteki is poor. At least mine. And play Karunā or Saisentan is expensive. So if you compare to the old Neural Katana maybe the strength is less but it tells the runner: "you have a nasty subroutine that you want to break unless you have your breaker/boat/boomerang on place". Anemone is the same price and is good but it's something that you want to time well when to rez it (the card that you're going to discard, how useful is going to be those 2 net damage). This is more "feel free to rez".

The extra strength on archives is cool, but think of that as an extra. Sometimes you need to ice archives and sometimes you have this ice and sometimes you need to ice something else.

Bathynomus does quite well against a popular killer (MKUltra) and is okay against most breakers on Archives, which could help on maybe 3-4 runs most games. It also fares reasonably well as an early draw against Aumakua decks but produces little value over time against Bukhgalter. If you find yourself frequently needing early Archives protection, which is rare, this is reasonable at $3. Off of archives, it usually has an impact of $0-1 except against MKUltra. Considering how little value ice on Archives usually produce, I think a fair rez price would be closer to $1 for an ice which is only semi-viable on Archives and nowhere else.

How does it do off-Archives? Most breakers besides MKUltra get through it for $0-1 off-Archives, which is so inexplicably bad for a $3 ice (or even a $0 ice) that rezzing it non-Archives gives the runner useful information about how desperate your draw has been. (On another central server, it suggests your draw has been starved for ice, which reduces the deterrent value of ice for your early game*. A remote Bathynomus suggests a lack of ice or possibly an exotic ZATO). Most other factions shy away from cards which are so bad that using them indicates you are in an existential panic. In Jinteki, you might not have a choice.

Unfrequently asked questions

Why would showing this card off-Archives weaken my position elsewhere? If I've drawn so few ice that I have to rez a Bathynomus off-Archives, I'm showing very low confidence in my ice draw, and the next ice I install will probably be whatever I draw next even if it's situationally terrible. It might be an ice I can't afford yet, a Bran that I don't particularly want to rez right now because it'd bankrupt me for too little short-term value, or a low-impact ice like Aiki on remote. In a situation like this, there's an above-average chance that the corp is not willing or able to rez that ice right now (or that it's unusually low-impact in its position) and that the runner can be more adventurous until they've seen otherwise. In contrast, if I lead with 2-3 ice early or if you access multiple ice from HQ, my installed ice are probably closer to what I was looking for rather than desperation installs.

Is Bathynomus an unusually terrible card? Not compared to most Jinteki cards, arguably. The worst 5 cards in a 2023 Jinteki deck will range from "how did something better NOT get printed?" up to "legit, is our card-pool actually worse than Adam's right now?" Depending on how worried you are that the ice is tied almost exclusively to the least important central server and not even all THAT good at defending it, this feels more like the second than the first.

Why no Aikis on remote? Remote server runs access cards which the corp has already paid to draw and install and also are more likely to be agendas. Aiki doesn't produce enough pain to create scoring windows on remote or adequately protect early assets. If you install a Rashida and they let Aiki fire, you're probably losing more from Rashida getting trashed than they are from Aiki's subroutines. If the run to trash Rashida was on R+D instead, I think you're probably ahead on the exchange with Aiki firing. (You have invested fewer resources into an R+D Rashida than one that you've drawn and installed).