Batch mcts-m2. Model 0.1.0, graph 0.2.0, parameters 0.1.0. 50 simulations, seeds 1 to 50; probes on 5. Every figure is a distribution over simulations of a structural model with seed parameter values; it shows what the model implies under these settings, not what will happen. Other nations are frozen at their 2026 ratings. No reconstructed historical data is used in this experiment.
Headline
South Korea played 20 rounds from 2026 under the greedy method, with stochastic events, 50 times. Its capability index moved from 16.00 to a median of 17.98 (+1.98), with 90 per cent of simulations between 17.43 and 18.43 [experiment_objectives].
Starting position
In 2026 the nation ranks 6 on the index against the frozen field, holds 2 of nine domains at Tier 1 and has a tier rank of 7. Its base income is 888 credits a year, calibrated so that its 2026 position is affordable with headroom for investment.
What was decided
A simulation spent a median of 3,444 credits on actions. The five groups that took most were Transparency, Oversight & Accountability (build, 142 credits, 4.1 per cent); Technical & Vocational Skills (build, 133 credits, 3.8 per cent); Public Integrity & Anti-Corruption (build, 122 credits, 3.5 per cent); Justice System & Fundamental Rights (build, 113 credits, 3.2 per cent); Political Institutions & Civic Participation (build, 110 credits, 3.1 per cent) [experiment_decisions_by_group]. By mode: build 58 per cent, buy 23 per cent, partner 19 per cent [experiment_decisions_by_group]. Concentration of spending (HHI) had a median of 0.026, and the most repeated action appeared in 15 per cent of rounds.
The leading domain by period: rounds 1 to 5, Human Capital; rounds 6 to 10, Governance & Integrity; rounds 11 to 15, Governance & Integrity; rounds 16 to 20, Critical Technology [experiment_spend_by_period].
The method's chosen action was within 5 per cent of its best alternative in 87 per cent of actions and ahead by more than 25 per cent in 0 per cent [experiment_decision_margins].
What the world did
A median simulation saw 2 shocks and 1 upside events. The most damaging per firing were S03 (19 firings in 18 simulations, −29.4 points each); S09 (5 firings in 5 simulations, −23.7 points each); S07 (6 firings in 6 simulations, −22.7 points each) [experiment_shocks]. Upside events fired 67 times across all simulations [experiment_shocks].
The groups that lost most to shocks, per simulation: Fiscal Capacity & Public Finance −1.18; Economic Leverage & Dependence −1.15; Trade Facilitation & Logistics −1.14; Information Environment & Strategic Communication −1.08 [experiment_shock_damage_by_group].
The edges that carried most change through the graph, per simulation: Research Talent & Knowledge Creation to Innovation & Commercialisation (+0.60 points); Research Talent & Knowledge Creation to Quantum Technologies (+0.59 points); Fiscal Capacity & Public Finance to Social Infrastructure (+0.46 points) [experiment_propagation_by_edge].
Where it ended
At 2046 the median rank is 2 (5th to 95th percentile 1 to 2), the median count of Tier 1 domains 7 (6 to 7) and the median tier rank 2; the resilient score, the mean score sum over simulations, is 1,298 [experiment_objectives].
Tier 1 probability changed most in: financial strength (0 to 100 per cent of simulations); governance and integrity (0 to 100 per cent of simulations); information and influence (0 to 100 per cent of simulations); strategic infrastructure (0 to 82 per cent of simulations); trade and investment (0 to 100 per cent of simulations) [experiment_tiers_by_round].
Why
Without shocks the index ends +0.131 higher on average, so the shocks cost about 0.131 index points [experiment_probe_attribution].
Holding instead of following this method changes the index by −2.370: that is the method's worth against doing nothing [experiment_probe_attribution].
Removing any single one of the five largest actions changes the index by between −0.021 and −0.005, for example 2045 buy Robotics & Autonomous Systems (53 credits) [experiment_probe_attribution]. The largest actions by credits come late, when income is highest, and are rarely the most valuable.
Removing the largest shock of a simulation raises the index by +0.065 on average [experiment_probe_attribution].
The replay probe reproduces the simulations exactly (index change 0.000000), so the attributions are clean [experiment_probe_attribution].
Surprises
move_without_shock (warn): largest one-round change in a group with no shock landing: 3.20 points; 4% of simulations have one above 3.
tier_jump (warn): largest gain in one domain within five years: 6 tiers (50 simulations above 2); tiers are reported, not an objective.
saturation_high (warn): 96% of simulations end with a group at 20 that did not start there (median 8 groups).
The simulation furthest from the median (seed 45) ends −0.84 from it, with 6 shocks and 0 upside events [experiment_outlier_simulations].
Comparison
This is the baseline (hold) experiment, or there is none for this nation in the batch.
No backcast comparison: this experiment does not start from a historical position [experiment_against_history].