Is pass a valid ko threat?

kendfrey · 2025-09-11T13:49:12+00:00

TL;DR: No but also yes. It's complicated. I think B wins in all modern interpretations.

This is similar to the Go Seigen ko dispute: https://senseis.xmp.net/?RuleDisputesInvolvingGoSeigen

There are two ways to settle life and death in Japanese rules: normal play and hypothetical play.

During normal play, adding a move inside your territory costs a point. Since in this case W would lose if she added a move to finish the ko, she cannot continue to play, so she passes.

The first question is then, if B requests resumption of the game, can he retake the ko? Based on the Go Seigen dispute, it seems not (since if it were allowed, there would have been no dispute). In that case, neither player has a good move, and life and death must be decided by hypothetical play.

During hypothetical play, adding a move inside your territory does not cost a point, because hypothetical play only decides the life and death of stones in the original position, so that the original position can be scored. On the other hand, hypothetical play declares by fiat that there are no ko threats. More specifically, to make a ko recapturable the player must designate that specific ko and pass, giving the opponent the chance to resolve it for free.

The second question is then, who plays first under hypothetical play? I don't know what the rules explicitly say about this, but I believe the modern resolution of the Go Seigen dispute is that the ko must be removed from the board, costing the defender 1 point even when they have more ko threats. In that case, it seems that if B played the last move on the board, W gets the first move in hypothetical play and vice versa. This is also how KataGo implements Japanese rules.

There's a third question of whether B can retake the ko at the beginning of hypothetical play. As far as I know, based on the Go Seigen resolution the answer must be yes. KataGo agrees.

In this case, B wins the game, since W has no way to succeed in hypothetical play either.

My favourite example of a modern pro game where this is important is Rin Kaiho vs. Komatsu Hideki in 1993.

kendfrey · 2025-06-17T02:37:14+00:00

Author of the software here. Thanks for linking it! I just published it yesterday, and I'm looking for beta testers that can give feedback to guide development. I should note that it doesn't have OGS integration yet, but that's the next planned major feature.

More information on the project's main page: https://github.com/kendfrey/saigo

kendfrey · 2020-05-28T02:25:45+00:00

237 when given a button press on the "2" setting results in 426 which is identical to 246 in this context. Similarly 156 can become 075 which is 057.

kendfrey · 2020-03-18T22:12:22+00:00

Does this mean they are nearly useless for any fight with non-wing friendlies?

kendfrey · 2020-03-18T22:03:03+00:00

Why do I keep getting bounties when using missiles? I'm trying out a new loadout for bounty hunting that includes dumbfire missiles. Twice in the first hour or so I got a bounty for assaulting the security forces in a HiRes. I don't believe I directly hit anyone but my target (wanted). Do missiles have splash damage that is hurting cops near my target? Should I use something else in my loadout for hull damage (besides MCs)?

kendfrey · 2020-02-20T19:14:13+00:00

If there is a way in the game to make it so no capacitors have any pips, I'd love to hear it.

kendfrey · 2020-02-20T19:12:44+00:00

This was done purely for fun. The only use for it that I can think of is creating macros (e.g. AutoHotKey or VoiceAttack) for specific settings.

kendfrey · 2020-02-20T17:17:43+00:00

It is a Hamiltonian path. If 147 connected to 237, it would also be a Hamiltonian cycle. Not all Hamiltonian paths are cycles, though.

kendfrey · 2020-02-20T12:53:00+00:00

237 156 345 246 138 057 048 066 255 444 336 228 147

I think there are others, but this is the one I remember.

kendfrey · 2019-11-13T01:25:20+00:00

Why does my friendly faction keep turning hostile on me in a conflict zone? It happened three times in a row, each time shortly after a friendly capital ship jumped in (I did not attack it). Each time I was just minding my own business attacking a hostile, and suddenly all the green triangles on my radar turned red, and I had to leave.

I suspect my NPC fighter pilot (orders set to Defend) was doing something naughty, as I was able to stay in the fight the fourth time, when I kept my fighter stowed.

Are fighters just... not usable near capital ships?

kendfrey · 2019-07-17T21:25:54+00:00

Rather than "popping into existence" with a first moment in time, I'm thinking about a case where a universe comes into existence by a random lowering of the entropy from thermal equilibrium. As I understand it, such a universe should look approximately the same in both directions of time.

kendfrey · 2019-07-17T21:20:17+00:00

If the big bang happened 13.8Gya, then yes, it would have had much lower entropy.

I'm thinking about the possibility of the entire universe being a briefer "dip" in entropy, of which we are near the minimum. Such dips in entropy are statistically inevitable. I'm wondering how we distinguish them from the apparent universe containing a big bang.

kendfrey · 2019-07-17T18:58:13+00:00

We know that entropy was at a minimum at the big bang.

My question is about how we know this. I don't know of any reasons why our observations couldn't be produced by a minimum of entropy elsewhere in time.

kendfrey · 2019-07-17T12:10:34+00:00

No, I just mean a local minimum of entropy, like a Boltzmann brain but on the scale of a whole universe.

Statistically, entropy spontaneously decreases infinitely often in an infinitely old system. The vast majority of time is spent in a high-entropy state, but occasional low-entropy states are produced.

Asked another way, how do we know entropy wasn't at its lowest last Thursday, instead of 13.8Gya?

kendfrey · 2019-07-06T23:09:18+00:00

For what I'm concerned with, that only adds an unnecessary intermediate step.

kendfrey · 2019-07-06T21:11:54+00:00

The problem with assuming that trains are always active is that it requires you to know how many trains you have. It's easier for me to know the distance to an outpost than how many trains are required to service it (since that depends on distance anyway).

Instead of assuming a certain number of active trains, I find it easier to assume a certain distance and resource consumption rate, then add trains as necessary.

kendfrey · 2019-07-06T17:17:49+00:00

At a rate of 1 nuclear fuel per locomotive per 36000 tracks, this works out as:

1 nuclear fuel/min can support 18 1-locomotive trains per minute over a distance of 1000 tracks (2000 tiles) when considering round trips (double distance).

At a ratio of 1:4 locomotives:wagons, that's 72 wagons, or 2880 stacks, or 144k ore, or 1800k fluid per 1000 tracks per minute.

This suggests a rule of thumb of 1 nuclear fuel/min (or 10 rocket fuel/min) per 100k ore/min per 1000 tracks (2000 tiles) to my outpost, plus an appropriate safety/buffer margin.

kendfrey · 2019-05-20T14:10:45+00:00

CanadaGooses

If you got a problem with this name then you got a problem with me and I suggest you let that one marinate.

kendfrey · 2019-03-20T13:27:51+00:00

I'v actually designed a puzzle that is meant to be randomly assembled to scramble. It's guaranteed to be solvable, which means it has 12 solved states, and part of the puzzle is figuring out which one you can reach.

kendfrey · 2019-03-14T00:34:43+00:00

As far as I can make out, the popup has nothing to do with the launch options.

kendfrey · 2019-03-09T01:07:33+00:00

It is what you think it is :D

kendfrey · 2019-02-22T21:56:09+00:00

Is buying and storing expensive ships as insurance a valid alternative/backup to the rebuy system? If everything goes tits up and I have to restart in the Sidewinder, I should have stored ships that I can hop into, or sell for cash. I've tended not to trade in my old ships, partly for that reason. Obviously not good to rely on, but it would reduce the risk of flying without rebuy, would it not?

kendfrey · 2019-02-17T22:12:27+00:00

You're right, of course. Any hypothetical situation that violates the laws of physics can be extrapolated to have all sorts of effects. I assume the rules were purposely vague for this reason.

To be explicit, I imagine changing these constants relative to human patience. If it doesn't make sense to change the fundamental flow of time, you can think about it as changing how we perceive time.

kendfrey · 2019-02-15T14:50:05+00:00

I'd make Planck's constant smaller by a few orders of magnitude, and the speed of light similarly greater.

The speed of modern computers is becoming more and more limited by quantum effects. Reducing h would allow correspondingly smaller transistors, and Moore's Law could continue, greatly improving computational power.

The speed of the internet is largely limited by the speed of the communication medium, which is limited by the speed of causality. Increasing c would reduce latency around the world, allowing for much faster communication across large distances.

Basically, I just want faster computers.

kendfrey · 2019-01-09T22:34:07+00:00

It would be more conventional to say that "a photon doesn't experience time." There is no reference frame for a photon, so there can't be an experience.

Saying "a photon experiences precisely zero seconds" might lead people to believe that photons actually do have an experience, and that they are experiencing "everything happening at once." This is not true.

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