The Arena

Faithful, self-hosted reproductions of documented, open web challenge mechanisms. Each gate has its own page that auto-serves the challenge — go there with a browser, a bot, or your own solver and test the bypass. You get two verdicts at once: did you pass the gate — and what does Kitsune’s detector independently make of your client over the edge?

The punchline the arena makes live: a solved challenge is a cost or Turing test, not a bot/human discriminator. A script can bypass any gate here and still be convicted on the network layer — coherence + attestation is the durable signal, not the puzzle.

Pick a gate to bypass

Verify-you-are-human checkbox
reCAPTCHA-v2 / Turnstile checkbox
The familiar "click to confirm you are human" checkbox. The click triggers a silent coherence check — a coherent client passes on the click with no puzzle; an incoherent one is stepped up to a proof-of-work. The detector AS the gate.
Managed challenge
Turnstile-style ladder
A silent coherence check first — a coherent client passes with no puzzle; only an incoherent one is stepped up to a proof-of-work. The detector AS the gate.
Hashcash proof-of-work
Proof-of-work · anubis
A SHA-256 leading-zeros proof-of-work, solved in your browser. A cost gate — not a human test: a script solves it just as well.
Many-small proof-of-work
Proof-of-work · friendly-captcha
N small SHA-256 sub-puzzles (the friendly-captcha shape), solved in-browser.
Memory-hard proof-of-work
Proof-of-work · Argon2id
An Argon2id memory-hard puzzle — GPU/ASIC-resistant by design. Bring the reference solver; the browser just shows the challenge.
Distorted-text CAPTCHA
CAPTCHA · distorted image
Read the warped, noisy text rendered to an image — the answer is in pixels, not markup, so it falls only to OCR. The gate the HuggingFace TrOCR evader beats.
Arithmetic CAPTCHA
CAPTCHA · logic
Answer a small arithmetic question — the classic text Turing test.
Analog-clock CAPTCHA
CAPTCHA · read-the-clock
Read the analog clock face and type the time it shows (H:MM) — a clock rendered at a random time (owned procedural, zero-license). A visual-reasoning task (interpret the hour + minute hands), distinct from glyph OCR; minutes are a multiple of 5.
Honeypot trap
CAPTCHA · hidden field
A hidden field a human never sees but a naive form-filling bot fills. Leave it empty to pass — submitting a value trips the trap.
Slider puzzle
CAPTCHA · GeeTest-style drag
Drag the block into the gap. The gate scores the drop position AND the drag trajectory's velocity variation — a constant-velocity glide or a teleport is rejected.
Image-select grid (emoji)
CAPTCHA · reCAPTCHA-v2 style
Pick every tile matching the prompt ("select every animal") from a grid of real emoji glyphs (Noto Emoji, OFL) — a category-recognition task that needs a real CV/VLM, not a shape classifier.
Image-select grid (doodles)
CAPTCHA · reCAPTCHA-v2 style
Pick every tile matching the prompt ("select every animal") from a grid of hand-drawn sketches (Google Quick, Draw!, CC BY 4.0) — open wobbly polylines with huge intra-class variance, even harder for CV than the emoji grid.
Rotate-upright puzzle
CAPTCHA · Arkose/FunCaptcha style
Drag the object upright. The gate scores the rotation trajectory, so a bare submitted angle won't pass — you must actually drag it round (variable angular velocity = human).
PACT personhood token
Defense · Private Access Tokens
An anonymous proof-of-personhood token that SKIPS the challenge — the frontier defense. The honest caveat: the issuer mints freely here, so it is also the documented bypass.
Audio spoken-digit CAPTCHA
reCAPTCHA / hCaptcha audio (accessibility)
Transcribe a spoken-digit clip — the ASR-benchmark twin of the distorted-text (OCR) gate. The clip is synthesised in pure Go from an embedded spoken-digit corpus, distorted per level; a correct answer faster than the clip's real-time playback is ASR automation (server-observed), so a solver passes the gate but is convicted on coherence.
3D spatial cube grid
Arkose / FunCaptcha 3D object
Select every cube with the target colour on top — a grid of isometric cubes rendered at random 3D orientations. Spatial reasoning (identify the TOP face of a rotated cube), not a 2D glyph; a correct selection faster than a human can scan the grid is automation, convicted on coherence.
How this works & the ethics

The gate is a self-hosted service Kitsune runs (the owned arena service). It reproduces the documented, open mechanism above — it never contacts, proxies to, or solves a third-party challenge (Cloudflare Turnstile, reCAPTCHA, hCaptcha). The reference solvers only ever talk to our own gates. The detector verdict comes from the same coherence engine that scores the home page, reading your client over the edge.