Mr. Jack

Readiness

ready (confidence=0.88, rules=0.90, fun=0.85). BGG rank: 801; year: 2006; weight: 2.17; playtime: 30 min

Core Loop

Mr. Jack is a two-player deduction game set in Victorian London. One player is Jack the Ripper hiding among eight suspects; the other player is the Inspector trying to identify and catch Jack. At the start, Jack secretly draws one of the eight character cards — that character IS Jack. Both players move all eight characters around the board (a constrained district of Whitechapel with gas lamps and alley entrances).

Each round has four character activations — two per player, alternating who picks first each round. Each character has a unique special ability triggered when activated. After all four activations, Jack checks visibility: if Jack's character can be "seen" (connected by line of sight through lit gas lamps to any character of the Inspector), Jack calls out "I am visible." If not seen, Jack says "I am not visible." The Inspector uses this binary information across rounds to eliminate suspects. Characters who are definitely not Jack can be identified through logical deduction based on the visibility statements. The Inspector wins by correctly accusing the right character; Jack wins by surviving eight rounds or escaping off the board.

Turn Structure and State

• BGA tutorial is present; useful for exact turn flow and implementation gotchas.
• BGG description anchor: In Mr. Jack, one of the two players represents Jack the Ripper, who will be one of the eight characters on the board. This player knows which character is Mr. Jack, and his goal is to flee from the district as soon as possible (or avoid being accused for eight turns). The other player represents an independent investigator (not represented on the board) who tries to guess the identity of Jack — but he can [...]

Win Condition and Arc

Inspector wins: correctly accuse Jack's character at any point (wrong accusation loses immediately). Jack wins: survive eight rounds without being caught, OR escape off the board via an alley exit (available from round 5 onward). The tension escalates as the Inspector's deduction space narrows each round.

Decision Primitives

BGG mechanisms: Grid Movement, Hexagon Grid, Open Drafting, Variable Player Powers

Memory-derived primitives:

• Hidden identity (one of eight known characters is Jack)
• Binary visibility deduction (seen / not seen after each round)
• Shared character activation (both players move all characters, not just their own)
• Action selection with diminishing choice (pick 2 of 4 revealed cards each round; opponent takes the other 2)
• Character special abilities (each of 8 characters has a unique power — move an extra space, rotate gas lamps, block alleys, etc.)
• Escape mechanic (Jack can flee off the board after round 5)

v4 controlled primitives: partial_observability, variable_player_powers, info_asymmetry_stable, _other:shared_character_drafting

Top iOS archetype fits: snap 5.7, balatro 5.3, coop 5.1.

Why It Is Fun

The binary information system creates elegant deduction — each round gives exactly one bit of information, but character positions and ability use leak additional meta-information. The shared activation is brilliantly tense: both players are manipulating the same pieces toward opposite goals. Short play time (30 min) allows for quick rematch with sides swapped.

Player-voice evidence:

• A simple yet fun puzzler for two players. Needs more plays to determine final score.
• After having played Mr. Jack Pocket 20 times, I have finally given its big brother a try. The tactics are great, and the player powers add so much depth. Great asymmetrical game that perhaps suffers from slightly askew balance between...
• the wife will play this anytime...such a solid, fun little game.
• 2000+ owners can't be wrong. A good 2-player version of Where's Waldo.
• A chess-like game will plenty of strategies, yet as a chess-like game, 2 persons with clear skill level difference will result in a one-sided game

Friction and Failure Modes

• Treat Sonnet-memory edge rules as draft until confirmed by manual, BGA, or transcript.

Translation and Design Hooks

• Use this card to ask: which primitive carries the fun if theme/licensing is removed?
• For iOS, look for short-session compression, clear state visualization, and a digital-only twist.
• For new tabletop design, look for the tension source and decide whether to preserve or invert it.

Edge Rules and Gotchas

• Alley barriers and gas lamps can be rotated/manipulated by certain characters, disrupting visibility lines mid-round
• If Jack uses a character's ability in a way that contradicts what the Inspector expected, that itself leaks information
• Some characters can move other characters (creating complex board states)
• The Inspector can make an accusation at any point — early accusation is risky but can end the game fast
• Round 4-8: the game can end via escape or accusation, not just time-out

Sources Used

[
  {
    "kind": "bga_tutorial",
    "path": "data/bga_tutorials/21763.md",
    "quality": 0.85,
    "note": "BGA implementation rules summary"
  },
  {
    "kind": "bgg_comments",
    "path": "data/bgg_comments/21763.txt",
    "quality": 0.75,
    "note": "positive/player-voice sample"
  },
  {
    "kind": "llm_memory",
    "path": "data/llm_memory_sonnet/21763.md",
    "quality": 0.65,
    "note": "sonnet-self-rated-8"
  },
  {
    "kind": "github_code",
    "path": "data/code_implementations/21763.md",
    "quality": 0.6,
    "note": "GitHub implementation signal"
  }
]