At 02:21 on the morning of September 19, 2026, Beijing time, the verified Kimi account on Zhihu published a post with no words in it. One hundred and thirty-five digits: 415926535897932384626433832795… and on for another hundred. Eight hours later the first English-language relay on X had decoded it. Pi is 3.14159265358979…; remove the leading 3.1 and the remainder is, digit for digit, what Kimi posted. By late morning UTC the reading was everywhere: Kimi K3.1 is coming.
This page is the record for Kimi K3.1: what Moonshot has actually said (nothing, beyond the digits), what the rumor chain said before this and when, and what Moonshot’s own release cadence implies. It sits beside our trackers for Grok 4.8, Fable 5.2 and GPT-6 Sol, and it is written the same way: every claim dated, every absence checked and named. Times are UTC unless marked Beijing.
On this page · 11 sectionsOpen
At 02:21 Beijing time on September 19, 2026 (18:21 UTC, September 18), Kimi’s verified organization account on Zhihu posted 135 digits and nothing else. The digits are pi’s decimal expansion starting right after 3.1, which is why the whole market read them as Kimi K3.1.
That is the entire official record. Moonshot’s model list, pricing page, news index, the Kimi K3 repository on Hugging Face and OpenRouter’s catalog carry no K3.1, no kimi-k3.1 id, no date and no spec as of 13:20 UTC on September 19.
The rumor is older than the post. A July 31 industry note relayed by Chinese aggregators said K3.1 would ship in August with open weights; August passed without it. On August 20 users reported a third-party tool quietly labelled K3.1; on August 22 an anonymous Code Arena model, korrine, was guessed to be K3.1 because K3 had tested as kivine.
Moonshot has never named a .1 model. Its line runs K1.5, K2, K2 Thinking, K2.5, K2.6, K2.7 Code, K3, plus dated builds such as kimi-k2-0905. A K3.1 would be the first point release in the company’s naming.
The cadence is the only calibration. Gaps between Moonshot releases have shortened from 172 days (K1.5 to K2) to 34 days (K2.7 Code to K3). K3 shipped 65 days ago today, already longer than the last three gaps.
K3 is the model any K3.1 would follow: 2.8 trillion total parameters, 104 billion active, a 1,048,576-token context window, GPQA Diamond 93.5 per Moonshot’s model card, $3.00 per million input tokens and $15.00 output on Moonshot’s own API, open weights since July 27.
This is a living tracker. When Moonshot names K3.1 on kimi.com, platform.moonshot.ai or Hugging Face, or a model id, a price or a launch post appears, the confirmed facts land here the same day beside a scorecard of every claim above.
§ 01What we actually know
| Claim | Status |
|---|---|
| Kimi K3.1 exists | Not said by Moonshot; inferred from a digit post on Kimi’s verified Zhihu account (02:21 Beijing, September 19) |
| The post decodes to 3.1 | True: the 135 digits equal pi’s expansion immediately after 3.1; we checked against 200 digits |
| The post is authentic | Two independent screenshots show the same digits on the account with Zhihu’s verified-organization badge; the post itself is behind Zhihu’s login wall, so we could not open it |
| Release date | Nothing from anyone; a July 31 report said August, which passed |
| Open weights | Claimed by the July 31 report; nothing from Moonshot |
| Size, price, context, benchmarks, model id | Nothing exists |
| Moonshot surfaces (model list, pricing, news index, Hugging Face, OpenRouter) | No K3.1, no kimi-k3.1 (read 13:20 UTC, September 19) |
| Kimi on X | Silent; last post September 9 (Kimi Work remote control) |
| Anonymous checkpoints | korrine on Code Arena (August 22) guessed as K3.1, never confirmed; adamant-ananke floated the same week |
§ 02What Kimi posted, and what it decodes to
The post itself is the shortest primary source we have ever tracked. No caption, no image, no hashtag. The account is the one Zhihu marks 已认证机构号, a verified organization account, and the timestamp in both screenshots reads 2026-09-19 02:21, which is 18:21 UTC on September 18. We have not been able to open the post: Zhihu shows anonymous readers a verification wall and its API returns nothing for the account’s pins from outside China. What we can verify is the arithmetic. The string matches pi’s decimal expansion from the third digit onward for all 135 places, and the digit that would come next is 3.
The first English relay we can date came from @MaxForAI at 10:19 UTC: “Kimi’s official channels haven’t formally announced K3.1 yet”, with the note that the flagship on the website and docs is still K3. Seventeen minutes later @NFT_Chen posted the same reading; at 11:02 @notjazii wrote that “we might see it next week” and that “k3 was around opus 5 level, so k3.1 might even mog fable 5”, which is a guess stacked on a guess. The skeptics were in the same threads. One reply: “this is not a hint, this is a company that took a math class and wants credit”. Another: “doesn’t it mean: there is no 3.1?” Both readings fit a post with no words in it. What does not fit is the timing: a verified company account posting pi minus 3.1 at two in the morning, seven weeks after a report said K3.1 was due, and the company saying nothing afterward.
§ 03The rumor chain, dated
| Date | What was said | Source | Weight |
|---|---|---|---|
| Jul 31 | K3.1 will launch in August and stay open-weight | An AI industry note, relayed by 什么值得买 on Aug 21 | Report; the date passed |
| Aug 20 | The third-party tool workbuddy quietly relabelled its Kimi model K3.1 | Bilibili users, relayed by 什么值得买 | Third-party label, unconfirmed |
| Aug 22 | An anonymous Code Arena model, korrine, is guessed to be K3.1 because K3 tested as kivine | 机器之心, relayed by 什么值得买 on Aug 26 | Codename guess; Qwen and MiMo V3 also proposed |
| Aug 26 | A rival codename, adamant-ananke, is floated for Moonshot’s next model | Relayed by 什么值得买 | Unsourced |
| Sep 19, 02:21 Beijing | Kimi’s verified Zhihu account posts 135 digits of pi after 3.1 | Kimi on Zhihu (screenshots) | The only first-party signal |
| Sep 19, 10:19 UTC | First English decode: K3.1 is coming | @MaxForAI on X | Relay |
Read the chain for what it is. Everything before September 19 is other people naming the model: a report with a date that failed, a vendor’s label nobody confirmed, a codename argument that had three candidates. The pi post is different in kind, because it comes from the company, and different in content, because it says nothing. A teaser without a word in it commits Moonshot to nothing, and that may be the point.
§ 04Moonshot’s release cadence
The one thing Moonshot cannot hide is its own history. Seven numbered releases in twenty months, each on a public page.
| Model | Announced | Days since prior | Primary |
|---|---|---|---|
| Kimi K1.5 | Jan 20, 2025 | Kimi on X, arXiv 2501.12599 | |
| Kimi K2 | Jul 11, 2025 | 172 | Kimi on X, moonshotai.github.io |
| Kimi K2 Thinking | Nov 6, 2025 | 118 | Kimi on X |
| Kimi K2.5 | Jan 27, 2026 | 82 | kimi.com model page |
| Kimi K2.6 | Apr 20, 2026 | 83 | kimi.com, Hugging Face |
| Kimi K2.7 Code | Jun 12, 2026 | 53 | Kimi on X, Hugging Face |
| Kimi K3 | Jul 16, 2026 | 34 | kimi.com/news, Kimi on X |
| Kimi K3.1 | Not announced | 65 and counting | None |
Two things stand out. The gaps have shortened every cycle since January, and the current quiet stretch is already longer than the last three. That is consistent with a point release being close, and equally consistent with a company that shipped its largest model ever in July and is taking longer over the next one. Moonshot has also never used a .1 name: its habits are half-step increments (K2.5, K2.6, K2.7) and dated builds (kimi-k2-0905-preview is still in the model list). If the pi reading is right, K3.1 is a new naming convention as well as a new model.
§ 05What a K3.1 would follow
| Item | K3 |
|---|---|
| Total parameters | 2.8T (mixture of experts; 896 experts, 16 active per token) |
| Active parameters | 104B |
| Context window | 1,048,576 tokens |
| Headline benchmark | GPQA Diamond 93.5, per Moonshot’s model card |
| API price | $3.00 per million input tokens ($0.30 on a cache hit), $15.00 output, per Moonshot’s pricing page; third-party hosts on OpenRouter start at $1.70 and $8.50 |
| Weights | Open since July 27, 2026 (moonshotai/Kimi-K3) |
| Announced | July 16, 2026 |
Whatever K3.1 is, it starts from a 2.8T open-weight model with a million-token context and a $15 output price. The August rumor’s one concrete claim, that K3.1 stays open-weight, would put it in the same market as DeepSeek V4.1 Flash and GLM-5.3-Flash, both of which our DeepSeek tracker covers, and both of which shipped as documented releases, not riddles.
§ 06What would confirm it
- A line on kimi.com or platform.moonshot.ai. A news post, a model page or a kimi-k3.1 identifier in the model list. K3’s launch post and API arrived the same day.
- Weights. A moonshotai/Kimi-K3.1 repository on Hugging Face; K3’s weights followed its announcement by eleven days, so a weights-first release would be a first.
- A named checkpoint. Code Arena or OpenRouter attaching Moonshot’s name to korrine, adamant-ananke or a new codename.
- A second post with words in it. Kimi’s Zhihu, WeChat or X accounts saying the name.
- A price. Anything relative to K3’s $3.00 and $15.00.
§ 07Where CellCog stands
Our conflict, declared: we build CellCog, a platform where a business hires AI employees that keep memory and work as a team, and we choose the models underneath them. Today that is Claude Fable 5.1 at Core and Max and Gemini 3.8 Flash at Flash. We do not route to Kimi. We track Moonshot’s models the way an operator does, as candidate engines, and an open-weight K3.1 that is strong at long-horizon agentic work would get tested on our infrastructure the day it ships. Until then, this page records what has been posted and refuses to round it up.
§ 08What we are watching for
- Moonshot’s surfaces, several times a day: kimi.com/news, the platform model list, Hugging Face, OpenRouter.
- Kimi’s Zhihu and X accounts for a second post, or for the first post being deleted.
- Code Arena for korrine or any new anonymous model attributed to Moonshot.
- Chinese tech press (机器之心, IT之家, 量子位) for a dated report with a source inside the company.
§ 09The tracker
This page updates when facts change, not when posts get louder. As of September 19, 2026: Kimi K3.1 has been named by aggregators, forum users and X accounts, and hinted at by Moonshot in a post of 135 digits and zero words. No date, no spec, no benchmark, no price exist in any Moonshot document. When Moonshot moves, the confirmed facts and a graded scorecard of every claim above land here the same day.
§ 10Update log
This is a living page; when the story moves, the update lands here.
As of September 19, 2026, 13:30 UTC: page opened. Kimi’s Zhihu post read from two independent screenshots (02:21 Beijing); the digits verified against pi; Moonshot’s model list and pricing page read in a browser at 13:20 UTC, the news index, the K3 model card and OpenRouter’s catalog at 13:10 UTC, zero mentions of K3.1; Kimi’s X timeline read at 13:05 UTC, last post September 9.
§ 11Sources
- Kimi on Zhihu, verified organization account, post of 2026-09-19 02:21 Beijing time, read from screenshots posted by @MaxForAI (10:19 UTC) and @notjazii (11:02 UTC); @NFT_Chen (10:36 UTC); @kimmonismus (11:13 UTC). Post times computed from post ids.
- Moonshot AI, Kimi K3 announcement, July 16, 2026; Kimi K3 open weights, July 27, 2026; model list and pricing, read September 19, 2026, 13:20 UTC; moonshotai/Kimi-K3 model card.
- Release dates: Kimi K1.5, Kimi K2, K2 Thinking, K2.5, K2.6, K2.7 Code, K3.
- The rumor chain: 什么值得买, Kimi K3发布满月, August 21, 2026 (relaying the July 31 note and the August 20 workbuddy reports); Kimi K3.1疑似灰测, August 26, 2026 (relaying 机器之心’s August 22 korrine report).
- OpenRouter, kimi-k3 endpoints, read September 19, 2026 (Moonshot’s own endpoint at $3.00 and $15.00; third-party hosts from $1.70 and $8.50; no K3.1).
Q1Has Moonshot announced Kimi K3.1?
No. We read Moonshot’s model list, pricing page and news index, the Kimi K3 repository on Hugging Face and OpenRouter’s model catalog at 13:20 UTC on September 19: zero mentions of K3.1 and no kimi-k3.1 identifier. The only thing from the company is the digit post, which names nothing.
Q2Is the pi post really from Kimi?
The screenshots circulating on X show the post on the account labelled Kimi with Zhihu’s verified organization badge, stamped 2026-09-19 02:21, and two independent screenshots carry the same 135 digits. Zhihu blocks anonymous readers, so we could not open the post itself; we say so here rather than pretend we did. Nothing matching it appears on Kimi’s X account, which had last posted on September 9.
Q3Where did the K3.1 name come from before this?
From the Chinese-language rumor chain. A July 31 industry note, relayed by the aggregator 什么值得买 on August 21, said K3.1 would launch in August and stay open-weight. On August 20 users on Bilibili reported the third-party tool workbuddy labelling its Kimi model K3.1. On August 22 机器之心 covered an anonymous Code Arena model, korrine, that many guessed was K3.1 because K3 had tested anonymously as kivine; other guesses were Qwen and Xiaomi MiMo V3, and a rival codename, adamant-ananke, was also floated.
Q4How fast does Moonshot ship?
Faster each cycle, until now. K2 followed K1.5 by 172 days; K2 Thinking by 118; K2.5 by 82; K2.6 by 83; K2.7 Code by 53; K3 by 34. Sixty-five days have passed since K3 without a numbered release, the longest quiet stretch since January.
Q5Should I wait for Kimi K3.1?
For a model without a date or a spec, no. Kimi K3 is available today on Moonshot’s API, on OpenRouter and as open weights. If you are choosing where your agents run, the model underneath matters less than the layer around it: memory, task board, inbox and approvals a person can see. CellCog runs Claude Fable 5.1 at Core and Max and Gemini 3.8 Flash at Flash; we do not route to Kimi, and we would test K3.1 the day it ships.