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Achilles Desk — Player Manual

Everything you need to play your first tape, read your score, and understand what the game is actually measuring.

1. What this is (and what it isn't)

Achilles Desk hands you a masked slice of real market history and asks you to trade it — solo, against a friend's ghost, or in a live room of up to 500 players. The chart is real — a real stock, index, or asset, on real days — but the name and the dates are hidden. You decide one trading day at a time. When the tape ends, the mask comes off and you learn what you were actually holding, which is frequently humbling.

Three things to know before you tap anything:

The money is simulated. Every tape starts you with $100,000 of simulated capital. You cannot lose real money. You cannot win real money either — which is exactly the point: it isolates your decisions from your balance sheet.
You're practicing decisions, not picking stocks. Nothing here is a stock tip. The game trains decision hygiene under uncertainty — and measures the biases that quietly tax real investors: overtrading (action bias), the disposition effect (selling winners early, riding losers), hindsight bias, and sloppy position sizing. If those terms are new, the game will teach them when they bite you.
The history is real, so the lessons are real. Every tape actually happened to actual people with actual money. You get the lesson; they paid the tuition.

What this is not: a financial-literacy course. It won't teach valuation, accounting, or portfolio construction. It's an investor-behavior training instrument — it teaches decision process: sizing, costs, benchmarks, and knowing when you're lucky.

2. Four ways in

Pick whichever door you were handed.

1. Room code — a teacher, friend, or host gives you a short code. Type it on the home screen.

2. QR code — scan it with your phone camera. A room code with less typing.

3. Challenge link — a friend sends you a tape they've already played. Tap it and you play that exact tape.

4. Daily Tape — no invite required. One new tape every day; open the app and tap Today's Tape.

No account needed to start. Came in on a challenge link? You play instantly as a guest. An account only matters at the reveal — when the ticker is unmasked — and only if you want to claim your result and keep it. Don't care? Close the tab. Nothing is saved, nothing is held against you.

Sign-in options (ages 16+): Google, Apple, or an email code. Classrooms with younger students use a teacher-managed mode (see Section 10).

3. Your first tape: Plain Tape

Your first tape is a Plain Tape: three decisions, three buttons, no setup. It's the baseline — the game measures your raw decision instincts before any tools enter the picture.

3 decisions. The tape pauses three times and asks what you want to do.
3 buttons. Buy, Sell, Wait. That's the entire interface.
Zero jargon. No ticker, no technical terms, no settings menu to get lost in.

What a "turn" is: one turn = one trading day. Markets run about five days a week, so a two-week slice of history is roughly ten turns. On most turns the price moves and you watch. On a few, the game stops and asks for a decision.

The flow: the chart starts drawing with your $100,000 in cash and no position → the tape pauses at a decision point → pick Buy, Sell, or Wait → repeat twice more → the tape ends, and you get your score (Section 5) and the reveal (Section 6).

If you finish thinking "that was easy" — good. That's the design. Later tapes add tools, not confusion.

4. How a tape works after Plain Tape

Turns. Same rule: one turn, one trading day. A standard tape runs 10–20 turns. One tap advances the day; nothing rushes you unless you're in a timed mode.

Trade tickets. A ticket is one order — "buy this much" or "sell this much." You get about six per tape, and that's deliberate: enough to express a plan, not enough to mash buttons and call it a strategy. Spend them like they're real. The lesson certainly is.

Sizing: 25 / 50 / 100%. Every ticket asks how much — a quarter, half, or all of your available cash (or holdings, when selling). Sizing is the lever new players ignore and good players obsess over. A right call at 25% and a wrong call at 100% do not cancel out. Ask anyone who's tried.

The 3-second undo. After you confirm a ticket, an undo bar appears for three seconds. Tap it and the ticket vanishes. After that it's locked. It exists for input errors, not second thoughts.

Crux Days. Some turns are flagged Crux Days — the days that mattered most in the real history. The game won't tell you what happened (that would unmask the ticker), only that this one counts. Size carefully on a Crux Day.

The Street HUD. The default display, built for first-timers:

Exposure Tachometer — a dial showing how much of your money is in the market. 0% = all cash, nothing can touch you. 100% = fully in, every move lands in full. A speedometer for risk.
Plain-language tickets — orders read as sentences ("Bought with half your cash on day 7"), not codes.
Cash and position — what you have, what you hold, and what it's worth right now.

A Pro HUD with more detail unlocks as you climb the career ladder (Section 7).

5. Scoring, in plain English

The Achilles Score answers one question: how much better did you do than someone who did nothing — after costs, adjusted for the risk you took? Think of it as a Sortino-style ratio for the tape: excess return over the passive benchmark, penalized for downside risk rather than all volatility. Every clause in that sentence is load-bearing.

Than someone who did nothing. +10% feels great until you learn the market rose 15% while you were being clever.
After costs. Every ticket costs a little — commission, spread, market impact — exactly as in real life. Churn eats your result quietly, which is how it gets away with it.
Adjusted for risk. Two players finish +8%: one held calmly at 50%, the other yo-yoed 100% in and out. The calm one scores higher. Wild rides are penalized because wild rides are how real people get wiped out.

The Index Ghost. Your rival on every tape: a ghost that buys at the start, never trades, and holds to the end. It's the do-nothing option, given a pulse and a line next to yours on the chart. Beating it is harder than it sounds. Most people don't, most of the time. That isn't a flaw in the game. That's the lesson.

The luck band. The score screen shades the range purely random traders would have landed in. Inside the band? Can't tell skill from luck yet. Clearly above? Signal. Clearly below? Also signal — just not the kind you wanted.

"Ranked #4 despite #2 return." You will see this, and you will object. Example: "You ranked #4 despite the #2 return, because you sat 100% exposed through two Crux Days and burned all six tickets. Player #3 made less but risked far less." The game always explains itself in a sentence like that. If one doesn't make sense, tell us — that's exactly the feedback we want.

6. The reveal

The tape ends. The mask comes off. Three things happen:

1. Ticker and dates revealed. ("That was Netflix, January–March 2022.")

2. The 60-second teardown. Three parts: what happened (the real story), what this tape taught (the decision lesson), and what it didn't teach (one tape is one sample — don't generalize from it).

3. Claim or close. Guests are asked whether they want an account to keep the result.

Tape skill ≠ investing skill. Tapes make you better at reading a chart, sizing risk, and not panicking. They do not mean you can predict markets or should open a brokerage account tomorrow. Real investing involves taxes, time horizons, and information you don't have. The game will remind you of this. Repeatedly. On purpose.

7. The career ladder

Your rank is a career title, not a number. It rises with tapes played and process shown. It never falls — and you can always play at a simpler level (see Downshifting, below).

| Rung | How you get there | What unlocks | |---|---|---| | Intern | Create an account | Plain Tape, Street HUD, Daily Tape | | Analyst | 5 tapes completed | Pro HUD toggle, full score decomposition | | Associate | 10 tapes + above-median calibration | Conviction Commit reason tags, "Show What I Missed" slider | | Senior Associate | 15 tapes | Factor-attribution notes, all 12 learning objectives | | VP | 20 tapes + top-quartile calibration | Professional ethics scenarios | | PM | 30 tapes | Exam-style teardown items, Decision Record eligibility |

Your profile shows the ladder and your distance to the next rung ("3 more tapes to Associate — Pro HUD unlocks"). The unlock moment is the reward. There is no loot box.

Downshifting is free. Want to replay a Plain Tape as a VP? Switch back to Street HUD because Pro is noisy today? Go ahead. It never costs progress, never touches your title, never shows up as a demotion. Simplicity is a tool, not a punishment.

8. Ways to play

Daily Tape — one new tape a day, the same for everyone. Play it and your streak grows. Compare with everyone else who played today.
Ghost Duels — race a recorded player on the same tape, their decisions replaying in real time. Duel a friend's recording, a stranger's, or a top player's. The Index Ghost joins in, making it a three-way race you may well finish third in.
Desks — clubs. Join or found one and play weekly fixtures: a set tape, a set week, Desk vs. Desk. An intramural league, with charts.
Challenge links — finished a tape and quietly certain your friend would do worse? Send the link. Same tape, side-by-side comparison, argument settled.
Hosted Events — a host (often a teacher) runs a room on a schedule: same tape, same time, host-controlled pace and reveal. See Section 10.

9. Sharing

Tape Receipts. After every tape you get an auto-generated share card: your score, your line vs. the Ghost, the tape's lesson. It's masked — no ticker, no dates — so friends can click through and play it blind, and nobody can mistake your receipt for a stock tip.

Desk Record. An opt-in credential for LinkedIn and similar (off by default). It shows your process — tapes completed, consistency, calibration over time, career rung. It does not show P&L. Nobody serious hires on simulator profits; some may notice good process. It's earned through play, never granted.

10. Classroom notes

Reading this because a teacher sent you? This part's for you.

The teacher runs the room. They pick the tape, start it, pause it, and trigger the reveal. You play when it's your turn.
Class rooms are walled. Nothing appears on public leaderboards, Daily Tape rankings, or Tape Receipts unless your teacher enables it. Classmates see you; the internet doesn't.
Grading is on process, never luck. Teachers see thesis quality — the short reason you write for each trade ("buying 25%: the drop looks like one-day panic, not a trend"). A well-reasoned losing trade grades better than a lucky winner. Yes, really. Enjoy the one place where that's true.
Under-16 students play in a teacher-managed mode without personal accounts.

11. FAQ

Is it real money? No. Simulated, every tape, always.

Do I need finance knowledge? No. Plain Tape assumes nothing; terms are taught when you need them, not before.

What if I literally know nothing? Three buttons: Buy, Sell, Wait. That's the whole first game.

Can I lose? Simulated money, yes — and finishing below the Index Ghost is a lesson, not a bill.

Do I need to be 16? For a personal account, yes. Classrooms run their own mode.

How long does it take? One tape ≈ 6–8 minutes including the reveal. A Daily Tape fits a bus ride.

Can I replay a tape? Yes — but ranked scoring counts your blind run. Replays after the reveal don't move your score or streak. You already know the ending, and so does the game.

Why did I rank below someone who made less than me? Less risk, fewer tickets, lower costs. The score screen always says which.

12. Glossary

Tape — one masked slice of real market history you play through.
Masked — ticker and dates hidden until the reveal.
Ticker — a stock's short code (AAPL for Apple).
Turn — one trading day; one tap moves a day.
Trade ticket — one order to buy or sell; ~6 per tape.
Sizing — a ticket's share of your money: 25%, 50%, 100%.
Position — what you currently own. Exposure — how much of your money is in the market.
Exposure Tachometer — the Street HUD dial showing exposure as a percentage.
HUD — heads-up display; Street = simple, Pro = detailed.
Crux Day — a flagged turn where something big happened in the real history.
Achilles Score — your result vs. doing nothing, after costs, adjusted for risk.
Index Ghost — the buy-and-hold rival; the do-nothing option.
Luck band — the score range random traders would land in.
Risk-adjusted — scaled for how wild the ride was.
Reveal — ticker and dates unmasked. Teardown — the 60-second summary after.
Thesis — the one-line reason for a trade; graded in classrooms.
Tape Receipt — your masked share card after each tape.
Desk — a player club. Fixture — a scheduled Desk-vs-Desk match.
Downshift — playing simpler than your rung. Free, always.
P&L — profit and loss; raw money made or lost. Not on your record.

Value Capture vs. Value Creation

The lens from Competing in the Age of AI (Iansiti & Lakhani) — and the closing frame of every Read Achilles newsletter: in markets, value creation and value capture separate. The ones who create the value aren't always the ones who keep it.

Every tape is that separation, made playable. The asset created value during your window — the business compounded, earnings grew, the price moved. The only question is how much of it you captured: after transaction costs, after churn, after sizing mistakes, after panic. The Index Ghost captures the market's creation for free, by doing nothing. Your job was never to predict creation — it was to capture efficiently. Most active traders capture less than the Ghost. That's not an insult; it's the most important fact in investing, and now you've felt it firsthand.

For student readers — 5 feedback questions

1. Where did you get confused? Point to the exact sentence. ("Section 5, the luck band paragraph" is perfect.)

2. Was any word unexplained? List every term you had to guess at, even if you guessed right.

3. In your own words: why can someone rank above you with a lower return? If you can't answer, Section 5 failed — not you.

4. What made you want to play, or want to stop reading? Name the exact bits.

5. In one sentence: what is Achilles Desk?

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