Add 1650 checkpoint: Song reunification, Jianzhou Republic, Korean independence

Song dynamics:
- Northern Song collapses (Maunder Minimum + internal rot + southern expedition)
- New Song (Southern) reunifies most of China, capitalist-civilian government
- Jianzhou Republic: Liaodong industrial zone declares independence (oligarchic industrial republic)
- Innovation renewed by 50 years of war

Korea: independent + industrialized
- Garrison absorbed as military nobility, mines nationalized
- First true independence in 400 years, own industrial base

Northeast Asian conflict zone: Mongol Khanate / Jianzhou / Korea / Japan
- Four industrial states in close proximity, constant friction

Australia: Chinese settler semi-republic, tens of thousands, self-governing
- No other power interested

Maunder Minimum + silver inflation effects on other countries: TO BE DISCUSSED

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

1 files changed, 90 insertions, 9 deletions

diff --git a/WORLDBUILDING.md b/WORLDBUILDING.md
index 9dce94a..4911400 100644
--- a/WORLDBUILDING.md
+++ b/WORLDBUILDING.md
@@ -1706,12 +1706,93 @@ Key questions:
 
 ---
 
-## Open Questions (Post-1625)
-
-1. **Silver inflation**: Global impact of 80+ years of Potosí + Song split disruption?
-2. **Maunder Minimum** (~1645-1715): Coldest period — agricultural crisis everywhere. Who suffers most?
-3. **Egypt independence**: When? How does Ilkhanate respond?
-4. **Song reunification**: Does it ever happen? Or permanent split through V3?
-5. **England industrialization**: Coal/iron awakening — when?
-6. **Great Khanate**: Does serfdom reform happen or does the empire continue declining?
-7. **Remaining to 1836**: 211 years, ~8 checkpoints
+## 1650 Checkpoint: Song Reunification + Maunder Minimum
+
+### Northern Song Collapses (~1640s-1650)
+- Maunder Minimum (coldest phase begins ~1645) → northern agriculture collapses
+- Emperor repeatedly deposed by rival warlords (Dong Zhuo parallel, 40+ years of puppet emperors)
+- Industrial workers unemployed (factories running but no export markets, domestic market shrinking from famine)
+- Internal northern civil war: warlords fight each other while workers rebel
+- **Southern Song seizes the moment**: Northern expedition (~1648-1652?), exploiting northern chaos
+- Most of northern China falls to Southern Song relatively easily (northern system rotted from inside)
+- **Exception: Jianzhou (Liaodong/South Manchuria)** refuses to submit
+
+### Jianzhou Republic (建州共和国)
+- Song's oldest industrial zone (400+ year history) declares independence rather than accept Southern Song capitalist takeover
+- Ruled by military-industrial committee: factory managers + military officers + possibly worker representatives
+- **Not democratic** — oligarchic industrial republic (Venice/early Soviet hybrid)
+- Controls: Liaodong Peninsula, South Manchuria, heavy industry, weapons production
+- Nominally acknowledges Southern Song emperor? Or completely independent? **Fully independent — rejects both Song dynasties' authority**
+- Key asset: the most concentrated heavy industrial zone in the world
+- Key weakness: tiny population, no agricultural hinterland, surrounded by potential enemies
+
+### New Song (Southern Song reunifies most of China, ~1650)
+- Official name: still 宋, claims continuity. Legitimate emperor (from the southern line).
+- **Capital**: Hangzhou (or Nanjing?)
+- **Controls**: Jiangnan, Central Plains, most of former Northern Song territory, Huguang, Fujian, Guangdong, Yunnan-Burma corridor
+- **Does NOT control**: Jianzhou Republic, Western Protectorate (Xinjiang warlord), Sichuan (semi-autonomous warlord)
+- **Government**: Capitalist-civilian coalition. Emperor has real but limited power. Merchant/industrial interests dominate policy.
+- **Industrial base**: Southern-built industry (25 years of reconstruction, now mature) + recovered northern factories (damaged but repairable). Industrial center of gravity shifted south.
+- **Innovation renewed**: 50 years of war drove military-industrial innovation. New Song is technologically dynamic again (unlike the stagnant pre-split period).
+- **Southeast Asia**: Nominally acknowledges New Song but functionally independent patchwork. Malacca lost to Aceh.
+
+### Korea: Independent + Industrialized
+- Northern Song garrison absorbed into Korean political system after patron state collapsed
+- **Korean king offers deal**: garrison officers become Korean military nobility, keep some mine privileges, in exchange for loyalty to Korean crown
+- Most garrison members accept (no better option — can't go home)
+- **Mines nationalized**: Iron, coal, gold under Korean royal control
+- **Korea suddenly has its own industrial base**: nationalized mining + inherited Song technology + integrated Chinese military technicians
+- First truly independent Korea in 400+ years (since becoming Song tributary)
+- Relationship with New Song: cautious independence (New Song can reach Korea by sea but is too busy rebuilding)
+- Relationship with Jianzhou Republic: neighbors, potential rivals (competing industrial states), potential allies (both ex-Northern Song splinters)
+
+### Northeast Asian Conflict Zone (~1650+)
+```
+  Mongol Khanate (limited industry, independent)
+       ↕ (border tensions, mining rights disputes)
+  Jianzhou Republic (heavy industry, tiny population)
+       ↕ (rivals? allies? both ex-Northern Song)
+  Korea (nationalized industry, newly independent)
+       ↕ (historical enmity, Japan invaded twice)
+  Japan (isolated, colonizing Hokkaido)
+  
+  → Four small/medium industrial states in close proximity
+  → Constant friction: territorial disputes, trade competition, historical grudges
+  → V3 event chains: multi-way East Asian rivalry
+```
+
+### Australia: Chinese Settler Republic
+- Four waves of immigration (1400s fishing → 1470s crisis refugees → 1600s war refugees → 1640s famine refugees)
+- Northern coast settlements: several port towns, total population tens of thousands
+- **Semi-republican governance**: Acknowledges New Song emperor nominally but fully self-governing
+- Kongsi/cooperative model (similar to Lanfang Republic)
+- Beginning inland exploration → mineral discoveries approaching
+- **No other power interested**: Portugal passes by (Cape→Moluccas route) but doesn't settle. Too far from everyone except the Chinese world.
+- V3: autonomous Chinese settler colony, possibly 100k+ population by 1836
+
+### Silver Inflation + Maunder Minimum: Other Countries (TO BE DISCUSSED)
+
+Global context for 1650:
+- **Potosí silver**: 100+ years of production → massive silver accumulation in global economy
+- **Song split**: disrupted silver flows (silver used to flow TO Song → now where does it go?)
+- **Maunder Minimum**: coldest phase → agricultural crisis EVERYWHERE
+- **Industrial goods**: supply permanently multipolarized (Ilkhanate, Germany, Bohemia, Portugal, New Song rebuilding)
+
+Questions for discussion:
+1. How does silver inflation + cold snap affect European powers?
+2. Great Khanate: serfdom + famine = crisis point?
+3. Egypt: independence now? During Maunder Minimum chaos?
+4. Ilkhanate: how does it handle the cold snap with industrial capacity?
+5. India: unified but cold snap affects agriculture?
+6. Americas: colonial development during climate crisis?
+
+---
+
+## Open Questions (Post-1650)
+
+1. **Silver inflation**: Effects on each country/region
+2. **Maunder Minimum (~1645-1715)**: 70 years of extreme cold — who adapts, who collapses?
+3. **Egypt independence**: Timing and method
+4. **England**: Coal/iron industrialization trigger
+5. **Great Khanate**: Final crisis or survival?
+6. **Remaining to 1836**: 186 years, ~7 checkpoints