Ranged Accuracy and paid vertical movement adoption — 2026-09-09
Owner decision
New games use two live changes:
- Every ranged weapon gains +2 printed Accuracy. All melee weapon statistics, melee opportunity pools and melee rules are unchanged.
- Vertical movement is paid with movement points instead of climb caps, climbing Heat and falls. An ordinary-leg step costs the destination terrain entry plus one movement point per elevation level changed, uphill or downhill. Ordinary legs can cross any adjacent elevation change they can afford. Working Jump legs ignore the elevation surcharge in both directions and pay only destination terrain entry. Destroyed Jump legs use ordinary costs. Vertical movement adds no Heat. Voluntary and forced drops deal no fall damage and do not by themselves cause Prone or end movement; Throw, collisions and other rules retain their written effects.
Existing saves retain their embedded legacy vertical rules. The paid behavior is an explicit save/session capability, so an older battle is not silently reinterpreted.
The previous H3 contract allowed ordinary legs to climb at most one level for a +1 surcharge. Working Jump legs could climb one or two levels with no movement surcharge but added 1 Heat before every upward step; no mech could climb three or more levels in one step. A one-level descent added no surcharge. A drop of two or more levels dealt 1d6 + 1 per full 15 Weight to Legs through Armor and ended movement. The paid rule above replaces each of those clauses for new games.
Exact catalog change
The immutable before snapshot is parts-before.json, SHA-256 9a7206532e12d761533f13aa58632735e59d09fa93cfbddc3c49b5389b49ee41. The adopted data/parts.json snapshot has SHA-256 47f89c348498e18ffe091dedff126ac9ce02cd2e45b1d7bdae0b08000ee6a766. The machine-readable accuracy audit verifies that the only catalog differences between those two files are these eight non-melee acc fields:
| Ranged weapon | Previous Acc | Adopted Acc |
|---|---|---|
| Missile rack | +2 | +4 |
| Rifle | +3 | +5 |
| Autocannon | +2 | +4 |
| Cannon | +1 | +3 |
| Pulse | +3 | +5 |
| Flak | +3 | +5 |
| Rotary cannon | +1 | +3 |
| Lance | +3 | +5 |
Alternate ammunition and Energy Overdrive inherit their weapon's printed Accuracy. Their Shots, Pen, Damage, range, Heat and load rules do not change in this adoption.
The same exact audit confirms that the catalog's melee entries did not change. Blade remains Acc +2, Pen 3, Damage 2d6+2, Melee dice 2, Parry cost 1; Spike remains +2/2/2d6/3/1; Ram remains +1/4/1d6+3/2/2; Executioner greatblade remains 0/5/3d6+2/2/2. Shield remains a two-die Guard item. No melee pool, handling, class, pilot, parry or strike rule changed.
Evidence boundary
The earlier multivariant study tested an accuracy2 candidate under the former vertical-movement rules and under sampled bot policies. It found fewer empty proactive Fires, alongside candidate-specific lethality and first-side concerns. Those results informed the owner's choice but do not prove overall balance and do not predict the combined live ruleset after movement changed. No new simulation was run for this adoption.
Historical study files and conclusions remain unchanged. The study report has only an adoption addendum that separates this later design decision from its original no-advancement verdict. Fresh bot and human evidence should re-baseline ranged reliability, early deaths, wipes, map access, high-ground use, objective timing, Jump-leg value and activation-order effects under the combined live rules.
Independent review of the implementation and evidence boundary is recorded in the accuracy and vertical movement review.
Validation
The final integrated run passed all 549 tests across 78 files and TypeScript checking. All 26 browser checks passed: ten desktop vertical-movement cases and sixteen tablet movement/play cases, including restored legacy controls and stable board presentation. The independent reviewer approved the change after 123 focused passing checks. These checks validate implementation, compatibility and documentation; they are not balance evidence. No new simulation was run.
Start a new local match to use the adopted catalog and movement rules. Existing games retain their saved catalog and movement capability. Work remains on feature/local-playtest-prototype; this adoption does not deploy, push or merge the branch.