{
  "region_system_v3": {
    "description": "Scalable blacklist + frequent biomes system with mass requirements",
    "version": "3.0",

    "revolutionary_simplification": {
      "problem_solved": "Exponential complexity of biome compatibility (20 biomes × 50 features = 1000 combinations)",
      "old_system": "compatible_biomes + incompatible_biomes + probability (redundant and massive)",
      "new_system": "incompatible_biomes (blacklist) + frequent_biomes (priority) - NO probability"
    },

    "core_logic": {
      "default_behavior": "All features available everywhere by default",
      "blacklist_filtering": "incompatible_biomes = hard exclusions (geological impossibility)",
      "priority_system": "frequent_biomes = higher priority/likelihood in these environments",
      "mass_gating": "minimum_region_mass = geological strength requirements",
      "selection_method": "Filter by mass + blacklist, then prioritize frequent biomes"
    },

    "workflow_example": {
      "scenario": "Iron region (mass=200) placing feature in 'alpine' biome",
      "step_1": "Filter by mass: rich_iron_ore (≥150✅), iron_ore_vein (≥75✅), bog_iron (≥10✅), etc.",
      "step_2": "Filter by blacklist: remove bog_iron (alpine incompatible), keep rich_iron_ore + iron_ore_vein",
      "step_3": "Check frequent biomes: rich_iron_ore has alpine in frequent_biomes → HIGH PRIORITY",
      "step_4": "Result: rich_iron_ore selected (mass ok, not blacklisted, frequent in alpine)"
    },

    "scalability_advantages": {
      "new_biome_addition": "Automatically compatible with all features except explicit blacklists",
      "maintenance_load": "~3 blacklist entries per feature vs ~15+ whitelist entries",
      "geological_logic": "Blacklist = impossible formations, frequent = optimal conditions",
      "no_probability_management": "Eliminates probability balancing and normalization complexity"
    },

    "feature_examples": {
      "rich_iron_ore": {
        "incompatible_biomes": ["tropical_rainforest", "wetlands"],
        "frequent_biomes": ["hills", "rocky_plateau", "alpine"],
        "explanation": "Cannot form in tropical/wetland conditions, optimal in mountain/hill tectonics"
      },
      "laterite_iron": {
        "incompatible_biomes": ["alpine", "cold_desert", "tundra", "hot_desert"],
        "frequent_biomes": ["tropical_rainforest"],
        "explanation": "Requires tropical weathering, impossible in cold/dry conditions"
      },
      "peat_bog": {
        "incompatible_biomes": ["hot_desert", "cold_desert", "alpine", "rocky_plateau"],
        "frequent_biomes": ["wetlands"],
        "explanation": "Needs wetland accumulation, impossible in dry/rocky conditions"
      }
    },

    "files_updated": {
      "iron_regions.json": "7 features with blacklist+frequent system",
      "copper_regions.json": "6 features with blacklist+frequent system",
      "coal_regions.json": "6 features with blacklist+frequent system",
      "oil_regions.json": "7 features with blacklist+frequent system",
      "spatial_distribution_patterns.json": "5 random density patterns for regions"
    },

    "implementation_ready": {
      "phase_8_integration": "System ready for world generation Phase 8",
      "algorithm": [
        "1. Region assigned random pattern (concentrated/uniform/ring/clustered/gradient)",
        "2. Pattern determines density distribution within region radius",
        "3. For each feature placement:",
        "4.   - Check region.mass >= feature.minimum_region_mass",
        "5.   - Check local_biome NOT IN feature.incompatible_biomes",
        "6.   - Prioritize features where local_biome IN feature.frequent_biomes",
        "7.   - Select from available features",
        "8.   - Place according to region density pattern"
      ]
    },

    "maintenance_metrics": {
      "old_system": "1000+ compatibility combinations to maintain",
      "new_system": "~200 blacklist entries total across all features",
      "reduction_factor": "5x less maintenance, infinite scalability for new biomes"
    }
  }
}