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Focus Areas · Design document §3

Available from: ME01 (Copper Working) + O06 (Natural Philosophy), or F03 (Charcoal) + ME04 (Iron Smelting)

Also reachable in this focus (dual-path; home focus in parentheses): Wood Gas Production (MI13, from Mining); Internal Combustion Engine (MC09, from Mechanics); Biomass/Biogas (ES13, from Energy Systems); Gunpowder (WA10, from Warfare); Phase Exchange (TR16, from Trade).

23 breakthroughs — CORE 9 · STANDARD 11 · UNCOMMON 2 · RARE 1 — Classical – Modern

Builds on: Fire (1) · Observation (1) · Farming (1) · Mining (1) · Metallurgy (1) · Warfare (1) · Mathematics (1) · Philosophy and the Arts (5) · Thermodynamics (3) · Optics (2)

Leads into: Farming (1) · Mining (3) · Metallurgy (4) · Construction (1) · Seafaring (1) · Medicine (4) · Trade (1) · Textiles & Materials (2) · Water Management (1) · Mechanics (3) · Thermodynamics (3) · Optics (1) · Electricity (3) · Electronics (2) · Nuclear Physics (1) · Quintessic Physics (11) · Rocketry (3) · Materials Science (3) · Genetics (2) · Space Engineering (2) · Energy Systems (2)

The numbers count prerequisite links between this focus and the other. How to read the tables.

Overview

ID Breakthrough Tier Era Prerequisites
CH01 Alchemy CORE Classical ME01 + O06 (Natural Philosophy)
CH04 Distillation CORE Medieval CH01 (Alchemy) + F01
CH05 Oxygen Theory CORE Early Modern PH04 (Scientific Method) + CH04 (Distillation — acids)
CH06 Periodic Table CORE Modern CH05 + MA03 (Basic Algebra)
CH07 Organic Chemistry CORE Modern CH06
CH08 Explosives (non-gunpowder) STANDARD Modern CH07 + CH04 (Distillation — acids)
CH09 Petrochemistry STANDARD Modern CH07 + MI07 (Petroleum)
CH09-W Bio-Organic Synthesis STANDARD Modern CH07 + FA03 (Selective Breeding)
CH11 Polymer Science CORE Modern CH07 + (CH09 or CH09-W)
CH12 Catalysis STANDARD Modern CH06
CH13 Rocket Propellant CORE Modern (CH08 (Explosives) or WA10 (Gunpowder)) + TH01 (Thermodynamics)
CH14 Photochemistry UNCOMMON Modern CH06 + OP03 (Telescope — optics)
CH15 Greek Alchemical Tradition RARE Classical CH01 + PH01 (Formal Logic) + CU02 (Monumental Architecture)
CH19 Systematic Element Analysis CORE Early Modern CH04 (Distillation) + PH04 (Scientific Method)
CH20 Transmutation Practice STANDARD Early Modern CH19 (Substance-Elemental validated) + CH01 (Alchemy)
CH21 Philosopher's Stone STANDARD Modern CH20 + PH04 (Scientific Method)
CH22 Five-Phase Theory STANDARD Early Modern CH19 (Process-Elemental validated) + CH01 (Alchemy)
CH23 Generative Cycle Engine STANDARD Early Modern CH22
CH24 Phase-Destruction Warfare STANDARD Modern CH22 + WA-any (any military breakthrough)
CH25 Organic Synthesis Attempt CORE Modern CH07 (Organic Chemistry)
CH26 Closed-Loop Calorimetry STANDARD Early Modern CH22 (Five-Phase Theory) + TH01 (Laws of Thermodynamics)
CH27 Formless Reserve STANDARD Modern CH20 (Transmutation Practice) + TH02 (Refrigeration)
CH28 Helium Extraction UNCOMMON Modern CH06 (Periodic Table) + OP08 (Spectroscopy)

Prerequisite map

flowchart LR
  n_CH01["CH01 Alchemy"]:::CORE
  n_CH04["CH04 Distillation"]:::CORE
  n_CH05["CH05 Oxygen Theory"]:::CORE
  n_CH06["CH06 Periodic Table"]:::CORE
  n_CH07["CH07 Organic Chemistry"]:::CORE
  n_CH08["CH08 Explosives (non-gunpowder)"]:::STANDARD
  n_CH13["CH13 Rocket Propellant"]:::CORE
  n_CH09["CH09 Petrochemistry"]:::STANDARD
  n_CH11["CH11 Polymer Science"]:::CORE
  n_CH09_W["CH09-W Bio-Organic Synthesis"]:::STANDARD
  n_CH25["CH25 Organic Synthesis Attempt"]:::CORE
  n_CH12["CH12 Catalysis"]:::STANDARD
  n_CH14["CH14 Photochemistry"]:::UNCOMMON
  n_CH28["CH28 Helium Extraction"]:::UNCOMMON
  n_CH19["CH19 Systematic Element Analysis"]:::CORE
  n_CH20["CH20 Transmutation Practice"]:::STANDARD
  n_CH21["CH21 Philosopher's Stone"]:::STANDARD
  n_CH27["CH27 Formless Reserve"]:::STANDARD
  n_CH22["CH22 Five-Phase Theory"]:::STANDARD
  n_CH23["CH23 Generative Cycle Engine"]:::STANDARD
  n_CH24["CH24 Phase-Destruction Warfare"]:::STANDARD
  n_CH26["CH26 Closed-Loop Calorimetry"]:::STANDARD
  n_CH15["CH15 Greek Alchemical Tradition"]:::RARE
  n_CH01 --> n_CH04
  n_CH04 --> n_CH05
  n_CH05 --> n_CH06
  n_CH06 --> n_CH07
  n_CH07 --> n_CH08
  n_CH04 --> n_CH08
  n_CH07 --> n_CH09
  n_CH07 --> n_CH09_W
  n_CH07 --> n_CH11
  n_CH09 -.-> n_CH11
  n_CH09_W -.-> n_CH11
  n_CH06 --> n_CH12
  n_CH08 -.-> n_CH13
  n_CH06 --> n_CH14
  n_CH01 --> n_CH15
  n_CH04 --> n_CH19
  n_CH19 --> n_CH20
  n_CH01 --> n_CH20
  n_CH20 --> n_CH21
  n_CH19 --> n_CH22
  n_CH01 --> n_CH22
  n_CH22 --> n_CH23
  n_CH22 --> n_CH24
  n_CH07 --> n_CH25
  n_CH22 --> n_CH26
  n_CH20 --> n_CH27
  n_CH06 --> n_CH28
  classDef CORE fill:#dbeafe,stroke:#1d4ed8,color:#0b1b3b
  classDef STANDARD fill:#f1f5f9,stroke:#64748b,color:#0f172a
  classDef UNCOMMON fill:#dcfce7,stroke:#15803d,color:#052e16
  classDef RARE fill:#fef3c7,stroke:#b45309,color:#3b2005
  classDef UNIQUE fill:#fae8ff,stroke:#a21caf,color:#3b0a3f
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Prerequisites within this focus. Box colour is the tier (blue CORE, grey STANDARD, green UNCOMMON, amber RARE, purple UNIQUE); dotted arrows are alternatives (“or”); a line can pass behind another box, so follow it from its start. 14 of these 23 breakthroughs also need breakthroughs from other foci, which the overview above lists.

Breakthroughs

CH01 · Alchemy

CH04 · Distillation

  • Tier: CORE · Era: Medieval
  • Prerequisites: CH01 (Alchemy) + F01
  • Unlocks: Distilleryⁿ [140/1; +2 Gold; ⟨Provides [1] [Whisky] <when number of [Worked [Peat Cutting] Tiles in this city] is more than [0]>⟩] — spirits, essential oils, perfume; and where the city cuts peat, whisky. Whiskyⁿ — a new luxury resource (resourceType: Luxury; ⟨Doesn't generate naturally⟩), made rather than mined, as Jewelry and Porcelain are: malted barley dried over peat smoke. It needs a worked Peat Cutting in the distilling city — the peat is cut and burned — so every such city makes one, to enjoy or to trade. That peat is spent: a distilling city counts one fewer worked Peat Cutting toward its Charcoal Kiln's fuel (ME08). The mineral acids were themselves products of distillation — vitriol distilled into oil of vitriol, saltpetre and alum into aqua fortis — so the chemistry and electricity that need acids follow this row (Acid/Base Discovery, merged here in v3.105). Prerequisite for Oxygen Theory (CH05), Explosives (CH08) and Electricity (EL02).
  • Leads to: MD07 Anaesthesia, MD18 Humoral Pharmacology, MC09 Internal Combustion Engine, TH02 Refrigeration, TH11 Caloric Storage, CH05 Oxygen Theory, CH08 Explosives (non-gunpowder), CH19 Systematic Element Analysis, EL02 Voltaic Pile (Battery), ES13 Biomass/Biogas

CH05 · Oxygen Theory

CH06 · Periodic Table

CH07 · Organic Chemistry

CH08 · Explosives (non-gunpowder)

  • Tier: STANDARD · Era: Modern
  • Prerequisites: CH07 + CH04 (Distillation — acids)
  • Unlocks: Artillery (unit); ⟨[-25]% construction time for [Mine] improvements⟩ (blasting). The gunpowder-free explosive. Also discoverable through Mining.
  • Notes: Alternative for gunpowder-less games.
  • Leads to: CH13 Rocket Propellant

CH09 · Petrochemistry

CH09-W · Bio-Organic Synthesis

  • Tier: STANDARD · Era: Modern
  • Prerequisites: CH07 + FA03 (Selective Breeding)
  • Unlocks: Bio-Refineryⁿ [375/2; +1 Production; +2 Gold; ⟨Remove [Refinery] [in this city]⟩ — plastics, sealants and fuel grown rather than drilled]. Slower and land-hungry, but renewable. Competing Solution (§1.2): the alternative to Petrochemistry (CH09), detour margin ×1.5 while Petrochemistry exists in this world; if Petrochemistry is discovered first this is never developed, and if it arrives later this persists — it needs no Oil. The primary chemistry path in FOSSIL_FUELS_ABSENT worlds.
  • Notes: Nature made polymers first. What if we learned from it better?
  • Leads to: CH11 Polymer Science, RK02 Liquid Fuel Rocket

CH11 · Polymer Science

CH12 · Catalysis

  • Tier: STANDARD · Era: Modern
  • Prerequisites: CH06
  • Unlocks: ⟨[+1 Food] from [Farm] tiles [in all cities]⟩ — the Haber process: the canonical Fertilizer bonus, earned by chemistry. Also discoverable through Farming. The primary of the fixed-nitrogen Competing Solution; Nitrate Fertiliser (FA16) is its alternative.

CH13 · Rocket Propellant

  • Tier: CORE · Era: Modern
  • Prerequisites: (CH08 (Explosives) or WA10 (Gunpowder)) + TH01 (Thermodynamics)
  • Unlocks: Unlocks Rocketry focus; Propellant Worksⁿ [125/1; ⟨[+15]% Production when constructing [Siege] units [in this city]⟩]. Rocket Artillery, Mobile SAM (units — canonical Rocketry; Rocket Artillery requires Aluminum). The first rockets are weapons, made from the propellant itself (Solid Fuel Rocket, merged here in v3.103).
  • Leads to: RK02 Liquid Fuel Rocket

CH14 · Photochemistry

  • Tier: UNCOMMON · Era: Modern
  • Prerequisites: CH06 + OP03 (Telescope — optics)
  • Unlocks: Photography Studioⁿ [375/2; +2 Culture; Great Artist points 1; ⟨[+25]% spy effectiveness [in this city]⟩ (<when espionage is enabled>)]. Prerequisite for solar power (ES07).

CH15 · Greek Alchemical Tradition

  • Tier: RARE · Era: Classical
  • Prerequisites: CH01 + PH01 (Formal Logic) + CU02 (Monumental Architecture)
  • Unlocks: Alchemist's Guildⁿ [50/1; +2 Gold]; reveals Distillation (CH04), and the acids it yields, as a concept centuries early. Alexandria's alchemists getting practical results.
  • Notes: Alexandrian alchemists achieving practical results. Requires both proto-scientific reasoning and a mystical tradition.

CH19 · Systematic Element Analysis

  • Tier: CORE · Era: Early Modern
  • Prerequisites: CH04 (Distillation) + PH04 (Scientific Method)
  • Unlocks: Analytical Laboratoryⁿ [national wonder; 200/0; +2 Science; on completion ⟨Triggers a [Systematic Element Analysis] event⟩ and Reveals the fork this world takes: the Periodic Table (CH06) in Corpuscular worlds (~55%), Transmutation Practice (CH20) in Substance-Elemental worlds (~25%), Five-Phase Theory (CH22) in Process-Elemental worlds (~20%)]. The decisive experiment for FQ9 — exhaustive decomposition, and the moment you learn what matter is made of.
  • Notes: The question every natural philosopher asked. Three universes answer it three ways.
  • Leads to: CH20 Transmutation Practice, CH22 Five-Phase Theory, QM-E01 Fundamental Matter Theory

CH20 · Transmutation Practice

  • Tier: STANDARD · Era: Early Modern
  • Prerequisites: CH19 (Substance-Elemental validated) + CH01 (Alchemy)
  • Unlocks: Grants MATTER_THEORY — the Elemental Codex, as Five-Phase Theory (CH22) does for Process worlds; every prerequisite naming the Periodic Table (CH06) reads this token. Prima Materiaⁿ — a new stockpiled resource (formless temperament; Stockpiled, never placed on the map). Transmutation Hallⁿ [national wonder — one per civilisation; 300; maintenance 2; ⟨Provides [6] [Prima Materia]⟩; Scientist ×1 — no production at all: the Hall makes matter, not goods, and its two Gold of upkeep are the alchemists who are not at the forge. One Hall, not one per city: transmutation is a capital industry, not an empire-wide income — the physics calls it ruinous by hand, and the mine-head Vats, the Athanors and Dispersal are how it scales. (Verified in TurnManager.kt: each turn a civilisation gains its resource supply of every stockpiled resource, and Provides counts toward supply — so a building yields a stockpile directly, with no yield to convert. A negative production stat would also work — the engine sums building stats without a floor — but upkeep says the same thing more legibly, and specialists cannot yield stockpiles natively, so an Alchemist slot would need a further extension.) The loss the physics demands sits in the re-locking.] Where matter comes from, and how much: the Hall (6 a turn, one per civilisation); Dispersal, only in the Hall's city (2 Production → 1); the Reserve Vats (CH27), one per city, half of every worked mine's base yield; and the Philosopher's Stone (CH21), 6 a turn and a lump of 150 for the one civilisation that builds it. For an eight-city empire from the Hall's Early Modern arrival to a late-game finish, that is roughly Hall ~1,100, Vats ~800, Dispersal ~900 (at a steep cost in production), and ~850 more with the Stone — some 2,800 matter without the Stone and 3,700 with it. A three-city tall civilisation lands within a few per cent of that: its capital's larger output makes Dispersal its stronger lever, while its fewer Vats bank less. Wide leans slightly ahead, as intended; tall is not crippled. There is no Great Person of matter — the Substance world's one new mechanic is the resource itself. (Preliminary estimates; the Hall's 6 and the Stone's 6 are the dials.) Dispersalⁿ — a perpetual process in the build queue, like Wealth: ⟨Enables conversion of city production to [Prima Materia]⟩ at 2 Production → 1 Prima Materia, ⟨Only available <in cities with a [Transmutation Hall]>⟩ — a city with a Hall may turn its whole surplus to formless matter for as long as it chooses. This is true production banking: what is not needed this decade is dispersed and re-locked when it is. (Fork extension: Unciv's PerpetualStatConversion targets a Stat; it is extended to accept a stockpiled resource — the [stockpile] parameter type already exists — see §7.0.) Re-locking into the land. Matter is re-tempered into a mineral lode on a tile of your own territory. Mineral Crucibleⁿ [unit, Civilian; ⟨Unbuildable⟩; ⟨Can be purchased for [1] [Gold] [in all cities]⟩ + ⟨Costs [240] [Prima Materia]⟩; ⟨Can move immediately once bought⟩; mv 2; ⟨Can instantly construct a [Transmuted Iron Lode] improvement⟩ <by consuming this unit>, and the same unique for the Coal, Oil, Aluminum and Rare Earths lodes; ⟨Only available <in cities with a [Transmutation Hall]>⟩] and Noble Crucibleⁿ [the same, but ⟨Costs [400] [Prima Materia]⟩ and building a Transmuted Gold, Silver or Gem Lode]. Transmuted Lodes — eight improvements, the Transmuted Iron Lodeⁿ, Transmuted Coal Lodeⁿ, Transmuted Oil Lodeⁿ, Transmuted Aluminum Lodeⁿ, Transmuted Rare Earths Lodeⁿ, Transmuted Gold Lodeⁿ, Transmuted Silver Lodeⁿ and Transmuted Gem Lodeⁿ ( terrainsCanBeBuiltOn: [Land]; no turnsToBuild, so no Worker can ever build one — Unciv lets only instant construction place an improvement without a build time (MapUnit.canBuildImprovement) — though a Worker may repair one that has been pillaged; strategic lodes ⟨Provides [2] [Iron]⟩ and likewise [Coal], [Oil], [Aluminum], [Rare Earths]; noble lodes ⟨Provides [1] [Gold Ore]⟩, [Silver] or [Gems]; each lode's techRequired is the breakthrough that reveals its resource — Iron, Gold and Gems Ore Identification (S04), Silver Deep Shaft Mining (MI05), Coal and Oil — the fuels — once the civilisation knows the fuel by either route, discovering its seams or making it: ⟨Only available <after discovering [non-[{non-[Coal Discovery]} {non-[Blast Furnace]}]]>⟩ and ⟨Only available <after discovering [non-[{non-[Petroleum Discovery]} {non-[Internal Combustion Engine]}]]>⟩ in place of a single techRequired (improvements honour Only available: TileImprovementFunctions), Aluminum Aluminium Extraction (ME13), Rare Earths Rare Earth Extraction (MI11) — so a Crucible's Create action stays disabled until you know the form exists (instant construction is enabled only when canBuildImprovement finds no problem, and MissingTech is one: UnitActionsFromUniques, TileImprovementFunctions); ⟨Will not be replaced by automated units⟩; ⟨Pillaging this improvement yields approximately [+20 Gold]⟩). Transmutation is therefore repeatable and limited by land, not by city count: every lode displaces whatever the tile was doing, stands in your territory (Unciv's OutsideBorders building problem), and stops providing the moment it is pillaged — an improvement's Provides is counted over every owned tile, unpillaged ones only (CityResources.getResourceFromUniqueImprovedTiles) — until a Worker repairs it. The noble lodes are gold, silver and gems rather than the made luxuries of earlier drafts: a lode is mineral, and lead into gold is the alchemist's defining act. Re-locking into coin — or into friendship: Transmuted Bullionⁿ [unit, Civilian; ⟨Unbuildable⟩; ⟨Can be purchased for [1] [Gold] [in all cities]⟩ + ⟨Costs [40] [Prima Materia]⟩ — buy-only, like a Missionary bought with Faith, the coin a token and the matter the price; ⟨Can move immediately once bought⟩ — without this a purchased unit has no movement that turn (BaseUnit.construct) and the consume action is gated on movement (UnitActionsFromUniques); mv 2; ⟨Instantly gain [30] [Gold]⟩ <by consuming this unit> — four matter for three coin, the alchemist's loss made a rate; ⟨Only available <in cities with a [Transmutation Hall]>⟩]. Stockpile costs are charged on purchase (CityConstructions.purchaseConstruction), there is no per-turn purchase limit, and each cart is placed on the nearest free tile, so a city may buy and cash several a turn without stacking — the queue is never touched. Civ unique carried by this breakthrough: ⟨Gain [6] Influence with a [Transmuted Bullion] gift to a City-State⟩ — a Global template, which is how Unciv's gifting code (UnitActions.getGiftActions, checkCivInfoUniques = true) looks it up; it admits a civilian to the gift action. Why six: Unciv offers gold gifts only in 250, 500 and 1000 (CityStateDiplomacyTable), paying ~25 Influence for 250 early and 5 late (influenceGainedByGift), so a 30-Gold cart already buys Influence in a denomination gold cannot, at a better rate per coin; the sixth point is the premium for driving it there, so that cashing the cart and gifting the coin is never simply the better move. Higher would let Dispersal-fed carts hold alliances from a single city. So a Substance civilisation keeps a second treasury of matter: spend it on the strategic resource you lack, cash it at three-quarters value, or drive it to a City-State for alliance. Pricing anchor: every re-locking is priced in the gold Bullion would have returned — a permanent +2 of a strategic resource costs 240 matter (≈180 Gold), a permanent luxury 400 (≈300 Gold, about what the AI charges for one luxury for thirty turns) — permanent, that is, until pillaged; against the budget above, a whole game's matter buys about a dozen strategic re-lockings, or half as many luxuries, or some two thousand Gold. Balance sheet, from Unciv's own formulas: rush-buying costs (30 × production)^0.75 Gold — 2.5 to 4.6 Gold per point — and the universal Wealth process converts production to Gold at ¼. Banked through Dispersal and cashed as Bullion, production becomes Gold at ⅜ — half again better than Wealth, which is the Substance civilisation's edge, and it keeps the option of spending the matter on a resource instead. Banked and then rush-bought back, production returns about a tenth of itself: a loss so steep that no one will use matter as a substitute for building, only as a reserve for the turn a unit is needed anywhere, now. Preliminary, but the ratios are the point: gold must never be the weak use of matter, and matter must never out-produce production. Any form into any other, at a loss, with no new interface. In a FOSSIL_FUELS_ABSENT world the fuel lodes open through the charcoal and alcohol roads, so a Substance civilisation there can re-temper matter into the seams its world never laid down. Substance only.
  • Notes: Only in Substance-Elemental worlds (FQ9). The alchemists' dream, industrialised.
  • Leads to: CH21 Philosopher's Stone, CH27 Formless Reserve, QM-E02 Bound-Energy Release, QM-E09 Incorruptible Matter

CH21 · Philosopher's Stone

  • Tier: STANDARD · Era: Modern
  • Prerequisites: CH20 + PH04 (Scientific Method)
  • Unlocks: ⟨[Great Merchant] is earned [+15]% faster⟩ — every adept's gold, if not the Stone itself. Philosopher's Stoneⁿ [world wonder; 400; +3 Culture, +2 Happiness; Scientist ×1; Merchant ×1; Great Merchant points 2; ⟨Instantly provides [150] [Prima Materia]⟩ on completion; ⟨Provides [6] [Prima Materia]⟩ — a second furnace that never goes out]. Transmutation at scale: the civilisation that holds the Stone keeps the largest second treasury in the world, and strategic resources become effectively fungible for it. (Earlier drafts had the Stone turn half of every Market's gold into matter; the converter reads only a building's own yield — the Market's 2 Gold — so that was one matter a turn. A flat flow says what was meant.) There is no route from gold back into matter, so Bullion's exchange is one-way and cannot pump. Substance only.
  • Notes: The crown of the substance-elemental chain. Every court alchemist vindicated.
  • Leads to: QM-E06 Exotic Matter (Elemental), QM-E10 Temperament Medicine

CH22 · Five-Phase Theory

CH23 · Generative Cycle Engine

  • Tier: STANDARD · Era: Early Modern
  • Prerequisites: CH22
  • Unlocks: Cycle Forgeⁿ [190/2; +2 Production; Sage ×1; Great Sage points 2] — where the cycle is studied; its gain is its Sages. Sageⁿ (new specialist, Specialists.json: +1 Food, +1 Culture; Great Sage points 3 — slots in the Forge, the Calorimetry Hall and The Great Wheel). Great Sageⁿ (new Great Person by the standard recipe: Civilian; Is part of Great Person group [Great Person]; Unbuildable; Uncapturable). A Great Sage's life's work is one of the Five Turningsⁿ — Great Improvements on the Manufactory's pattern (Great Improvement; Will not be replaced by automated units; no turnsToBuild, so no Worker can build one — MapUnit.canBuildImprovement), each built by ⟨Can instantly construct a [Turning of Wood] improvement⟩ <by consuming this unit> (five such uniques on the Great Sage, one per Turning), and each only on its own element's land — which Unciv enforces without new code, since instant construction offers only improvements with no permanent building problem on the tile (UnitActionsFromUniques.getImprovementConstructionActionsFromGeneralUnique). On its tile, each Turning is a plain Great Improvement: Turning of Woodⁿ (Forest, Jungle — built on the feature, which stays, like a Lumber mill) ⟨[+3 Food]⟩; Turning of Fireⁿ (Desert, Plains, Volcanic) ⟨[+3 Production]⟩; Turning of Earthⁿ (Grassland, Flood plains) ⟨[+3 Gold]⟩; Turning of Metalⁿ (Hill, Tundra, Snow) ⟨[+3 Science]⟩; Turning of Waterⁿ (any land ⟨Can only be built on [non-[{non-[Fresh Water]} {non-[Coastal]}]] tiles⟩ — beside a river, lake, oasis or the sea; Unciv filters have AND and NOT but no OR, and several placement uniques are ANDed (TileImprovementFunctions), so the OR is written by De Morgan's law) ⟨[+3 Culture]⟩. Fed, each grants its phase to the whole realm. A Turning is fed when a Turning of the element before it in the generative cycle is there to feed it — one feeder to one beneficiary, so the number of fed Wood Turnings is the smaller of the Wood and Water counts. Carried by this breakthrough, one unique per phase, stacking for every fed Turning: Wood (spring, growth) ⟨[+15]% growth [in all cities] <for every [min([Owned [Turning of Wood] Tiles], [Owned [Turning of Water] Tiles] * (1 + [⁠[The Great Wheel] Buildings]))]>⟩ — water nourishes wood; Fire (summer, flourishing) ⟨[+15]% Production when constructing [All] buildings [in all cities] <for every [min([Owned [Turning of Fire] Tiles], [Owned [Turning of Wood] Tiles] * (1 + [⁠[The Great Wheel] Buildings]))]>⟩ — wood feeds fire; Earth (the centre, ground) ⟨[-20]% Culture cost of natural border growth [in all cities] <for every [min([Owned [Turning of Earth] Tiles], [Owned [Turning of Fire] Tiles] * (1 + [⁠[The Great Wheel] Buildings]))]>⟩ — fire makes earth, and the realm's ground settles outward; Metal (autumn, the blade) ⟨[+10]% Strength <for [Military] units> <for every [min([Owned [Turning of Metal] Tiles], [Owned [Turning of Earth] Tiles] * (1 + [⁠[The Great Wheel] Buildings]))]>⟩ — earth bears metal; Water (winter, wisdom) ⟨[+15]% Great Person generation [in all cities] <for every [min([Owned [Turning of Water] Tiles], [Owned [Turning of Metal] Tiles] * (1 + [⁠[The Great Wheel] Buildings]))]>⟩ — metal gathers water. The (1 + [⁠[The Great Wheel] Buildings]) term is The Great Wheel's rule — each Turning feeds two — folded into the same count, since Unciv counts a civilisation's buildings by name; without the wonder it is 1 and feeding is strictly one-to-one. How it is counted: Owned [tileFilter] Tiles matches an unpillaged improvement by name (Tile.matchesSingleFilter); <for every [countable]> multiplies any unique aggregated through UniqueMap.forEachMatchingUnique (forEachMultiplied); and countable expressions support min() and arithmetic on nested countables (Unique-parameters.md). No marker resource and no stockpile. What follows: one complete cycle — five Great Sages — returns fifteen tile yields and five policy-sized effects; beyond it, progress is incremental rather than all-or-nothing, since any extra Turning placed behind an extra of its feeder adds one more fed effect (a wheel plus a second Water and a second Wood holds six); a pillaged Turning drops out of every count, so raiding an enemy's Wood starves its Fire; and the terrain sets are chosen so that almost any start holds all five. The one loop to watch: fed Water raises Great Person generation, which yields more Great Sages — bounded, since each Water must itself be fed by a Metal. Civ unique: ⟨Gain [40] Influence with a [Great Sage] gift to a City-State⟩ — the gifting code destroys a Great Person given to a City-State but pays the Influence first (UnitActions.getGiftActions), so a Great Sage may instead be sent to teach a neighbour. Process only.
  • Notes: The wu xing answer to industry: the turning cycle feeds itself.
  • Leads to: QM-E06 Exotic Matter (Elemental), QM-E11 Full-Cycle Coupling (The Great Wheel), QM-E24 Self-Renewing Structures

CH24 · Phase-Destruction Warfare

  • Tier: STANDARD · Era: Modern
  • Prerequisites: CH22 + WA-any (any military breakthrough)
  • Unlocks: Phase Disruptorⁿ [unit, Siege; cost 300; mv 2; str 22; ranged str 35; range 2; ⟨[+25]% Strength <vs cities>⟩; ⟨[+25]% Strength <when attacking>⟩]; Elemental Wardⁿ [150/1; cityStrength +6]. The controlling cycle weaponised. Process only.
  • Notes: The five phases turned to war.
  • Leads to: QM-E25 Counter-Cycle Reversal

CH25 · Organic Synthesis Attempt

  • Tier: CORE · Era: Modern
  • Prerequisites: CH07 (Organic Chemistry)
  • Unlocks: Synthesis Laboratoryⁿ [national wonder; 300/0; +2 Science; on completion ⟨Triggers a [Organic Synthesis Attempt] event⟩ and Reveals the path: fully abiotic synthesis (Polymer Science, CH11) in Mechanist worlds (~70%), Vital Essence Isolation (GN12) in Vitalist worlds (~30%)]. The decisive experiment for FQ11 — urea from dead matter, as Wöhler did; and whether it works decides what life is.
  • Notes: The experiment that quietly killed vitalism in our world — and vindicated it in others, without closing the refinery.
  • Leads to: GN12 Vital Essence Isolation

CH26 · Closed-Loop Calorimetry

  • Tier: STANDARD · Era: Early Modern
  • Prerequisites: CH22 (Five-Phase Theory) + TH01 (Laws of Thermodynamics)
  • Unlocks: Calorimetry Hallⁿ [125/1; Sage ×1; ⟨[+1 Production] from all [Cycle Forge] buildings⟩ — better-tuned loops]; reveals the Generative Cycle Engine (CH23). The paddle-wheel of the wu xing: the sealed loop warms a little more than it should. Process only.
  • Notes: The paddle-wheel of the wu xing: the water warms a little more than it should.

CH27 · Formless Reserve

  • Tier: STANDARD · Era: Modern
  • Prerequisites: CH20 (Transmutation Practice) + TH02 (Refrigeration)
  • Unlocks: Reserve Vatsⁿ [500/3; +2 Gold; Merchant ×1; ⟨[50]% of [Production] from every [Mine] in the city added to [Prima Materia]⟩ — half of what every worked mine yields, echoed as matter at the mine-head]. One per city, so this is the source that leans wide: the converter reads a Mine's own +1 Production, not the tile's total, and truncates per city — eight cities working three mines each bank eight a turn, a tall capital working eight mines banks four. (It sums before truncating, CityResources.kt, so many mines add up where a fraction of one would vanish; a Quarry, with no base production, would yield nothing.) Substance only.
  • Notes: Nothing is wasted that can be bottled.

CH28 · Helium Extraction

  • Tier: UNCOMMON · Era: Modern
  • Prerequisites: CH06 (Periodic Table) + OP08 (Spectroscopy)
  • Unlocks: A lifting gas that does not burn. Ends the Airship Disaster for this civilisation — every airship's risk carries <before discovering [Helium Extraction]> — and a civilisation that holds it is unshaken by reports of other nations' disasters, since it knows the danger was the gas, not the airship. It does not restore confidence already lost. Liquid helium also opened low-temperature physics: Refrigeration (TH02, which now holds Cryogenics) and Superconductivity (EL11) cost ×0.8 for a civilisation that has it (a multiplier, §1.2).
  • Notes: Found first in the Sun's spectrum (1868) and named for it, which holds in any world; superconductivity was discovered in 1911 in mercury cooled by liquid helium. Helium was long a near-monopoly: the United States banned its export in 1927, which is why the Hindenburg flew on hydrogen.

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