Chiang Mai's a puzzle. Step into it.

Plan for about 4 hours of play, or about 5 with the four breaks. Progress saves, so you can stop for longer whenever you like.

A phone with a camera, mobile data and location turned on, charged full before you start. It runs in the browser on any recent iPhone or Android, so there's nothing to install. Bring water, a hat, sunscreen and comfortable shoes, and wear something that covers your shoulders and knees for the temple stops. In the wet season, add a light rain layer.

Shoulders and knees covered, for everyone. Every target is photographed from the street, a lane or the moat path, so you never need to go inside a building or a hall. If you do step into a temple ground, keep your voice low, take off your hat, and never sit or climb on a chedi, a wall or a statue. The game shows a short note before each temple stop.

Each answer is a building, a gate, a sign or a carving you can see from a public place. Stand where anyone can stand and photograph it; the game checks the picture in seconds. People are never the answer, so there's no need to photograph anyone, and nothing asks you to pose with anything.

About 7.4 km at your own pace, almost all of it flat, on old city lanes, footpaths and the bridges over the moat and the river. Footpaths can be narrow or broken in places, so look down as well as up.

Hot by late morning for most of the year, which is why the game starts at eight (07:30 from March to October) and is done by about noon. Drink often, take the breaks in the shade, and slow down when you need to. November to February is the coolest and kindest time to play.

Drink bottled water. Water machines on the lanes refill a bottle for about a baht a litre, and there's a 7-Eleven on almost every block. Temple grounds and the market have toilets; cafés are there for customers.

The roads either side of the moat are one-way, several lanes wide and busy with scooters. Cross at the lights wherever you can, check both ways even on a one-way road, and walk the footbridges over the water. Look up from your phone at every kerb.

At Si Phum, the north-east corner of the old city moat, where the roads round the moat meet. A red songthaew or a taxi app will drop you at the corner. A VS race starts somewhere else: you meet at a shared start on Tha Phae Road before the countdown.

The game finishes on the east bank of the Ping River, about 1.5 km from the old city. Walk back over the river, or flag a red songthaew or book a ride: both are easy to find on the riverside roads.

No. The whole game is on foot, with no ride in the middle, so the clock never has to pause. A ride can get you to the start and home again.

In some public places the anthem plays at eight in the morning and six in the evening, and people stop and stand still. If you hear it at the start, do the same for the minute it plays, then off you go.

Yes. The Sunday walking street fills the temple road from mid-afternoon, and a morning game is long over by then.

In March and April, smoke from farm and forest fires can make the air unhealthy: check the air quality the evening before and pick a clear day, or come another month. In mid-April, Songkran turns the moat into a water fight; it's great fun, and hard on phones, so play another week or bring a waterproof pouch. An unused code stays open for a year.

Yes. The riddles work for first-timers, and they're written to surprise people who have lived here for years: most of the 25 are things you can walk straight past.

Yes, if they're happy with the distance and the heat. Hold little hands near traffic and the moat's edge, take breaks whenever you need them, and keep everyone in the shade at the stops.

Four breaks are built in: coffee at Akha Ama in the old city, water and shade at a temple ground, Warorot Market for northern snacks and fruit, and a bowl of khao soi on a lane near the river. Hours can change, so check them on the day. Progress saves, so stop whenever you like.

Every stop is in a public place you can reach on foot, and you photograph from where anyone can stand. Cross at the lights, keep an eye out for scooters on the lanes and footpaths, watch your step on broken paving and beside the water, and look up from your phone at the kerb.

Every find can be photographed from a public place, so a shower need not stop you: bring a light rain layer, and a café is never far away. Wet-season rain often comes later in the day, another reason to start early. If the day looks wild, an unused code stays open for a year.

You never get stuck. Ask for the next clue whenever you like. If all five clues miss, the game shows you where the thing is, and walking within 25 m of it adds the piece. You just score a six for that stop.

The game lets you move on. A patchy location fix or a photo the checker can't read never ends your day: carry on to the next stop, and that piece shows as unlocked with help on your card.

Yes. Share one phone on one code, or link several phones so a find on one unlocks for everyone. Linked codes can also play Competitive as one team, with one name on the leaderboard, and race each other in VS.

No. Every code can play Solo, Crew, Competitive or VS, and testers pay nothing at all. Linked codes can play both: Competitive as one team, and VS against anyone, crewmates included.

Each mode comes with its own, each once per walk. Easy has its arrow, circle and thermometer built in, plus a Free skip. Medium has its arrow, plus a Free skip and a Thermometer. Hard has nothing built in, plus a Thermometer, a Compass and a Free skip. The Thermometer runs cold, warm, hot inside the search area and the Compass points to it, both until you solve that stop; the Free skip shows the next clue at once, with no wait and no extra move. Every 5 stops a quick question asks what you saw, and every right answer wins another lifeline. Competitive has Hard's three, strictly, and a crew playing as a team shares one set. A VS match plays the lifelines of the mode you both agreed on.

Yes, as long as they have their own Jigwalk code. There's no matchmaking: send the 6-character match code however you like, they choose Competitive and Join VS, and see the match's mode: Competitive unless you picked Easy, Medium or Hard when you made it. Pressing Ready means you both agree to it. A match that never starts closes after 12 hours.

Finished Competitive walks in Chiang Mai, VS matches on Competitive rules included, on two boards. A VS match on Easy, Medium or Hard is a friendly race, so it doesn't go on the leaderboard. Best score ranks the fewest moves first, with the faster time breaking a tie. Fastest ranks the quickest finish first, with fewer moves breaking a tie. Each line shows a nickname or a team name, then moves, time and lifelines used.

Not to play: your game code is all you type in. Free tester codes are claimed with an account, one claim per account for each city. The leaderboard only ever shows the nickname you choose at the finish.

English.

Until 7 days after you finish. If you haven't finished, it stays open for a year from when you get it.

Nothing, for now. Chiang Mai is free while we test it. Prices, the boxed puzzle and the finish treat come with the official launch.