Batch stress-preview. Model 0.2.0, graph 0.2.0, parameters 0.1.1. 100 simulations, seeds 1 to 100; probes on 25. 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 10 rounds from 2026 under the greedy method, with stress events, 100 times. Its capability index moved from 16.00 to a median of 16.71 (+0.71), with 90 per cent of simulations between 16.02 and 17.12 [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 1,014 credits a year, calibrated so that its 2026 position is affordable with headroom for investment.
What was decided
A simulation spent a median of 1,508 credits on actions. The five groups that took most were Lifelong Learning & Reskilling (build, 91 credits, 6.1 per cent); Technical & Vocational Skills (build, 91 credits, 6.1 per cent); Diplomatic Statecraft & Global Networks (partner, 90 credits, 5.9 per cent); Fiscal Capacity & Public Finance (partner, 72 credits, 4.7 per cent); Research Talent & Knowledge Creation (buy, 68 credits, 4.5 per cent) [experiment_decisions_by_group]. By mode: partner 36 per cent, buy 35 per cent, build 29 per cent [experiment_decisions_by_group]. Concentration of spending (HHI) had a median of 0.041, and the most repeated action appeared in 30 per cent of rounds.
The leading domain by period: rounds 1 to 5, Human Capital; rounds 6 to 10, Trade & Investment [experiment_spend_by_period].
The method's chosen action was within 5 per cent of its best alternative in 88 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 S01 (100 firings in 100 simulations, −34.1 points each); S03 (17 firings in 16 simulations, −32.9 points each); S07 (6 firings in 6 simulations, −23.1 points each) [experiment_shocks]. Upside events fired 76 times across all simulations [experiment_shocks].
The groups that lost most to shocks, per simulation: Economic Leverage & Dependence −1.71; Trade Policy & Market Access −1.59; Export Capability & Sophistication −1.57; Global Value Chain Position −1.57 [experiment_shock_damage_by_group].
The edges that carried most change through the graph, per simulation: Economic Output & Productivity to Fiscal Capacity & Public Finance (+0.26 points); Research Talent & Knowledge Creation to Innovation & Commercialisation (+0.25 points); Artificial Intelligence to Robotics & Autonomous Systems (+0.19 points) [experiment_propagation_by_edge].
Where it ended
At 2036 the median rank is 2 (5th to 95th percentile 2 to 6), the median count of Tier 1 domains 4 (3 to 6) and the median tier rank 4; the resilient score, the mean score sum over simulations, is 1,205 [experiment_objectives].
Tier 1 probability changed most in: financial strength (0 to 48 per cent of simulations); information and influence (0 to 99 per cent of simulations); production and innovation (100 to 73 per cent of simulations); strategic infrastructure (0 to 28 per cent of simulations); trade and investment (0 to 100 per cent of simulations) [experiment_tiers_by_round].
Why
Without shocks the index ends +0.794 higher on average, so the shocks cost about 0.794 index points [experiment_probe_attribution].
Holding instead of following this method changes the index by −1.277: 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 −0.024 and −0.020, for example 2036 buy Industrial & Sectoral Base (32 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 +0.477 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
tier_jump (warn): largest gain in one domain within five years: 6 tiers (100 simulations above 2); tiers are reported, not an objective.
saturation_high (warn): 69% of simulations end with a group at 20 that did not start there (median 1 groups).
The simulation furthest from the median (seed 65) ends −1.13 from it, with 5 shocks and 0 upside events [experiment_outlier_simulations].
Comparison
Against the hold experiment for the same nation (e5-kor-s01-hold), the median index is +1.26 points apart, the median rank 2 against 8, and Tier 1 domains 4 against 0 [experiment_against_hold].
No backcast comparison: this experiment does not start from a historical position [experiment_against_history].