Skip to main content

Territory Competition

Ownership on merca.earth is never safe. A neighbor can buy a slice of your land. You can expand into unclaimed territory and box someone in. Anyone can force a full buyout at any time.

This is not a side effect — it's the core mechanic. The map stays alive because every position is contestable. This page explains how territorial aggression works, what protections the defender has, and what the protocol physically prevents.

Acquire Slice — Forced Partial Acquisition​

acquire_slice lets you take a geometric piece of a neighboring parcel and add it to your own. The neighbor cannot refuse.

How it works​

  1. You define the new shapes for both parcels (yours grows, theirs shrinks).
  2. You pay for the acquired area at the donor's current market price (area × base rate × donor's premium_ppm). The donor receives their share automatically — same payment split as a full buyout (85% seller / 7% treasury / 8% hierarchy tax).
  3. The donor's premium_ppm stays unchanged. The receiver's premium_ppm becomes the area-weighted ceiling blend of the two parcels' premiums: ⌈(receiver_area × receiver_premium + slice_area × donor_premium) / new_receiver_area⌉. If the acquired slice carries a higher premium than yours, your blended premium rises.

The operation executes atomically in a single transaction.

Protections for the donor​

  • Automatic compensation. The donor receives fair market value for the lost area instantly. No claim step needed.
  • Minimum area. The donor's parcel cannot shrink below the level's min_area. If the slice would reduce the donor below this threshold, the transaction aborts.
  • Geometry validation. The resulting donor parcel must still pass all geometry rules — convexity, connectivity, compactness. You cannot carve the donor into an invalid shape.

What this means for you​

If you own land, a neighbor can always buy a piece of it. You receive compensation automatically, but you cannot prevent the slice. This is the Harberger principle applied to geometry: not just whole parcels, but parts of parcels are always for sale.

warning

You cannot block an acquire_slice. If you want to protect your territory, the best defense is owning the surrounding land yourself.

Expand Unclaimed — Claiming Free Territory​

expand_unclaimed (called via reshape_unclaimed) lets you grow your parcel into adjacent unclaimed land. No one owns unclaimed land, so there is no donor and no compensation — you pay only for the added area at your current premium.

How it works​

  1. You submit a new shape for your parcel that is larger than the current one.
  2. The new shape must fully contain the old shape (you cannot shrink or teleport).
  3. The added area must not overlap any existing parcel.
  4. You pay for the added area: added_area × base_rate × your premium_ppm.

Aggressive expansion​

There is no per-epoch limit on unclaimed expansion. If unclaimed land is available, you can absorb it as fast as you can submit transactions. This means a fast-moving owner can claim territory around a neighbor's parcel, restricting the neighbor's future expansion options.

This is intentional. Unclaimed land is a public good — first come, first served.

Why Full Encirclement Is Impossible​

A common concern: can an attacker surround your parcel on all sides, trapping you?

No. The protocol's geometry engine physically prevents this.

Every parcel is a union of convex parts whose outer boundary must form a single continuous cycle with no holes (Geometry Rules → Hole-free boundary). A ring-shaped parcel — one that surrounds another parcel's space — has two boundary cycles (outer and inner) and fails the validate_boundary_graph check with EInvalidBoundary.

This means an attacker can expand around you in a U-shape or an L-shape, but never a closed ring. You always retain at least one open direction for expansion or slice acquisition.

 ┌──────────┐
 │ Attacker │    ← U-shape: allowed
 │  ┌────┐  │
 │  │You │  │
 │  └────┘  │
 └──────────┘    ← Ring: REJECTED (EInvalidBoundary)

 ┌──────────┐
 │ Attacker │    ← L-shape: allowed
 │  ┌────┐
 │  │You │
 │  └────┘
 └──┘

Strategic Implications​

Defending your territory:

  • You can't stop neighbors from slicing, but you can make it expensive. The higher your premium, the more they pay per square meter.
  • Expand into unclaimed land before your neighbors do. Controlling the space around you limits their options.
  • If someone takes a slice, you're compensated at your current market rate automatically. Expensive land means expensive slices.

Going on offense:

  • Slicing a neighbor costs their market rate, not yours. A high-premium target is a costly attack.
  • Expanding into unclaimed land is the cheapest way to pressure a neighbor — it doesn't hurt them directly, but it cuts off their room to grow.
  • You can't fully surround anyone. The protocol forbids ring-shaped parcels, so there's always an exit.
Last updated on