How to play Operation 38th Parallel

What the game is

Operation 38th Parallel is a strategy game about a fictional war on real ground. At four in the morning the North's artillery opens fire along the whole Demilitarised Zone and its divisions cross the line in four places. You command the defence of the South for the first sixty days: its army and the United States forces in Korea, with the alliance behind you.

The places, the countries and the published equipment of their forces are real. The invasion, its course and every person in it are invented, commanders are named by their role, and no real leader appears. Civilians are what you protect, never a target, and there's no playable nuclear use.

Play it in your browser at https://operation38thparallel.earthablaze.com/play. The whole game is free, and you don't need an account to play.

Starting out

The start screen offers two ways in:

Take command: the full campaign, sixty days from the first barrage. It takes about two hours at 1×, much less at speed.
The Daily Front: the first ten days, the same war for everyone that day, with a leaderboard. See the Daily Front.

A new campaign walks you through seven tips: select a corridor, commit a reserve, set up counterfire, fly the collectors and strike, assign the missile batteries, set the speed, and look at the Desk. Press Skip tips to hide them.

The five jobs

Hold the line north of Seoul. Four corridors lead south. Kaesong–Munsan and Cheorwon lead to Seoul; Chuncheon and the east coast road lead round it. Commit the reserves where the North puts its main effort and rotate worn divisions out.
Silence the guns. Hundreds of guns and rocket launchers can reach Seoul. Counterfire radars see them fire, and your artillery and aircraft kill them.
Shoot down the missiles. Choose what each battery defends. Interceptors run out.
Protect people. Shelters, or the roads south. Those are the same roads the reserves and the supplies need.
Keep it from going over the edge. Deep strikes into the North work, and they move the escalation clock.

The details of each are in Orders and controls.

How a campaign ends

Sixty days pass. If the line holds north of Seoul, the counter-offensive can start from there. If it holds further south, you've lost Seoul's northern districts.
The North reaches the Han. Seoul north of the river is lost and the campaign is over.
The escalation clock reaches 100. The war has gone past the point where anyone could win it, and the game is lost.

The grade

The debrief compares your civilian casualties and the ground you lost, weighted to the roads to Seoul, with what the planners expected for the same days. The plan scores 1.00 and lower is better. Losing Seoul's northern districts costs a great deal. The debrief also shows the North's guns and launchers you silenced and the missiles you shot down.

Sound

The operations room has its own sound, a score and radio nets. The South Korean corps, artillery and air defence nets talk in Korean, with the English shown as they speak. The Americans and the UN Command's Commonwealth units talk in English. The speaker and note buttons in the top bar turn the sound and the music off, and M turns the sound off and on.