Choose a stopping time
This demo is restricted to adults 18+ and uses coins without cash value or prizes. Set session time and virtual-coin limits before playing, then stop at those limits. Raising a stake to recover losses does not improve expectation. If playing affects responsibilities or becomes hard to control, stop and seek suitable independently verified local support.
Own-site rules
These rules describe only this original virtual game. This guide does not determine legal availability of an external service, certify its fairness or promise income. The own-site 18+ restriction is not a statement about every jurisdiction’s legal age.
Wallet and manual restore
Settled balance and fractional payout carry persist in localStorage. Reloading during a round ends it without refunding its already deducted stake. Outside a round, refill restores 1000 coins when balance is below the smallest stake; it does not add 1000 or reset fractional carry. Hazard count, stake and refill are locked during play.
Expected return
Exact expected return is 97% for permitted stopping policies. The initial 3% reduction is applied once; conditional safe-branch compensation preserves expectation. Choosing coordinates or stopping changes risk and variance, not this expectation. A short session is not guaranteed to match it.
Technical data
There are no account, payment or identity-document forms here. Fonts, the visit counter, server and CDN requests can expose technical data including IP and browser details. Complete anonymity, third-party data use and cookie lifetimes are not established. Clearing cache alone may leave localStorage intact.
Frequently asked questions
Is this an operator website?
This independent KM 23 guide supplies its own free Edge Span Mines demo. Operator identity, domains, licence, apps, payments, support and commercial game equivalence have not been independently verified. No operator account or commercial link is supplied here.
What are the edge constraints?
Choose 3, 4 or 5 hazards on a 4×4 board. Hazards must touch both the left and right edges, while they must not touch both top and bottom edges together. Touching only the top, only the bottom, or neither is allowed. All 124, 475, 1048 legal layouts respectively are equally likely and remain fixed during a round. Connectedness is not required.
Can hazards touch the top edge?
With 3 hazards, A1, B2 and A4 is legal: it touches left, right and top, but not bottom. A1, B2 and D4 is illegal because it touches both top and bottom. B1, B2 and C4 is legal without touching top or bottom. Visible edge conditions constrain a complete layout, not a guaranteed safe cell.
How is value calculated?
Live value starts at 0.97 times the virtual stake. A safe reveal divides it by that cell’s exact conditional safe probability among the remaining compatible legal layouts. A hazard ends the round with zero return. Reveals change knowledge, not the hidden layout.
Explore the original free Edge Span Mines demo.
