The Val d'Orcia, south of Siena, is one of the few landscapes in Italy that a UNESCO citation has not ruined. Partly this is because the land is too steep and too dry to bend to the wishes of visitors; partly it is because the Tuscans who farm it have, for fifty years, refused to install the things that would make it easier. There are still only three proper supermarkets between Pienza and Monticchiello. The gravel roads remain gravel. The cypresses are, in the truest sense, working trees: planted as windbreaks for the Cinta Senese pigs that graze beneath them. What follows is a three-day walking-paced itinerary that treats the valley as its residents do, which is to say slowly, and with a long lunch.

Go in late May or the first ten days of June. The grass is long, the poppies are still out, the tour-bus season does not begin in earnest until 20 June. August is a different valley: hotter, busier, the light harsher, the osterias running on half-staff while the families travel. If late May is impossible, the second-best window is the second half of September, after the heat and before the harvest rush. Avoid July and August if you can. If you cannot, book dinner early and leave the car parked.

Base yourself, for all three nights, at an agriturismo between Pienza and San Quirico. A good one, family-run, is Il Pentolino, on the ridge above Monticchiello, fifteen minutes by gravel road from Pienza proper. Eight rooms, a single long table for dinner (three nights a week), and a vegetable garden that supplies about half of what the kitchen serves. Rates in May sit in the 140 to 180 euro range per night for two, breakfast included. Book direct; the commission-driven portals charge 20 euro more and return the favour by losing the booking.

The valley does not reward a schedule. It rewards whoever is willing to be late for the next thing.

Day one: Pienza. Drop the bags at the agriturismo and walk the last kilometre into town on the white road rather than drive. Pienza is the smallest of the three towns (about 2,100 residents) and the most intentional; Pope Pius II rebuilt it between 1459 and 1462 as what the humanists called a città ideale, and the grid is still legible. Make for the Piazza Pio II before noon to see the cathedral's travertine facade in profile light. Lunch at Sette di Vino, a tiny osteria on the Piazza di Spagna (six tables, two of them outside), where the pici cacio e pepe is the only pici cacio e pepe you will need to order all week. Afterward, the Corso Il Rossellino for Forno Marusco, the town's bakery since 1949, for a loaf of the local pane toscano (saltless, deliberately) to take back. The afternoon light on the stone is the reason the painters keep coming.

In Pienza, the other errand is cheese. The pecorino di Pienza (DOP since 1996) is made in three ages: fresco (20 days), semi-stagionato (60 days), and stagionato (120 days and up). Caseificio Cugusi, on the road toward San Quirico, is the serious producer; the farm shop lets you taste the three ages side by side and does not charge for the privilege. Buy the semi-stagionato. It travels. Dinner: back at the agriturismo, with whatever came from the garden and a bottle of the house Rosso di Montalcino.

Day two: Montalcino. Twenty-four kilometres from Pienza by the SP14, but it is the wrong road to take quickly. Leave mid-morning. Stop at the Abbazia di Sant'Antimo, below Castelnuovo dell'Abate, for the 11 a.m. Gregorian office (Monday through Saturday; Sunday is the sung mass at 11, which is longer and finer). The abbey is 12th-century Romanesque, built in creamy travertine, set in a field that in May is still ankle-deep in wild oat. Give it forty minutes. Drive on up into Montalcino itself for a late lunch at Taverna del Grappolo Blu on Scale di Via Moglio, where the pinci al ragù di cinghiale (wild boar) arrives with a decanter of the house Rosso.

Montalcino is the wine town. Brunello di Montalcino has been produced here since the 1880s, when the Biondi Santi family isolated the particular Sangiovese clone (BBS11) that gives the wine its structure; it was the first Italian wine, in 1980, to receive DOCG status. A serious visitor should book a morning rather than an afternoon tasting, and should call ahead. Tenuta Poggio delle Colline, a smaller family estate south of the town wall, takes visitors by appointment only and pours three vintages (typically a current Rosso, a Brunello five years back, and a Riserva from the library); the tasting costs 35 euro and lasts about 90 minutes. There is no gift shop. Buy what you want on the spot or not. The afternoon, back at the agriturismo. Sleep if you can. You earned it.

Day three: Montepulciano. Where Pienza is humanist-planned and Montalcino is a fortified wine village, Montepulciano is a long vertical Renaissance corso built out of brown travertine. Thirty-five kilometres from Pienza, sixty-five minutes by the SP146 (the slow road, the right one). Park below the walls at Porta al Prato and walk the Corso up. Allow ninety minutes; there are more cantine on the route than anyone expects. Contucci, in the palazzo on the Piazza Grande, has been making Vino Nobile di Montepulciano since the 1400s and does a free ten-minute tasting in the cellar under the palazzo. Lunch on the Piazza Grande, outside if the weather holds, at Osteria Acquacheta, which knows exactly what it is doing with a bistecca alla fiorentina and will apologise in advance if you want yours above medium-rare.

What to skip, for candour. The photogenic cypress line east of San Quirico (the Cipressi di San Quirico) is itself beautiful, but between 10 a.m. and 4 p.m. in June is packed with tripod photographers. See it at 6.45 a.m. from the gravel track south of the SP438, or not at all. Skip the themed medieval dinners advertised in Pienza; they are for buses. Skip the spa hotels above Bagno Vignoni, lovely and expensive and not the point of the valley.

Leave on the fourth morning by the SP146 toward San Quirico and then up toward Siena, with the pecorino in the boot and a bottle from Poggio delle Colline behind the driver's seat. The valley will hold its shape in the mirror for about twelve minutes, the cypresses receding into a blue line at the horizon. Then it will be Siena, and the feeling will start to fade. The Val d'Orcia is a rhythm, not a place. Three days is exactly enough to catch it.