Petiscos are not tapas, whatever the menus in tourist quarters imply. Tapas are a Spanish institution with its own rules about standing and moving on; petiscos are simply Portuguese food served in small plates so a table can order six things instead of two. The difference is that nobody expects you to leave.
Dux calls itself a taberna urbana — an urban tavern — and it sits on Rua Doutor Manuel Rodrigues in the Baixa. It is the address in this guide where a named food writer has put his name to specific modern dishes rather than to a tradition, which makes it the most reliable place in the lower town to know what you are ordering before you sit down. Two sources cannot agree on the house number, but they are four doors apart and that is a solvable problem.
What to order
Three dishes are on the record, from Nelson Carvalheiro, who has written about Portuguese food for years.
Caramelised goat cheese with honey. A whole small cheese warmed until it slumps, with honey over it and bread to push it around. It is the dish that tells you what kind of kitchen this is — not inventive, exactly, but confident about where sweetness belongs in a savoury course.
Açorda de camarão com coentros. This is the one to order if you order nothing else. Açorda is a bread pulp: stale bread worked into stock with garlic, olive oil and enormous quantities of coriander until it becomes something between a porridge and a sauce, with prawns folded through and often an egg stirred in at the end. It is peasant cooking in the strict sense — it exists because bread went stale — and served well it is one of the most distinctive things in Portuguese food. Foreigners are frequently unprepared for the texture. Order it anyway.
Fried squid with aioli. The safe order at the table, and the one that keeps a sceptical companion happy while you eat the bread pulp.
Beyond those three, nothing is documented. There is no published menu, so build a table around the known quantities and ask the waiter what else the kitchen is proud of.
The name is worth a second of thought too. Dux is Latin for leader, and in a university city where the older colleges taught in Latin and the students still wear black capes, a Latin name over a tavern door is a joke with a local audience. It also tells you the room is aiming at students and young professionals rather than at coach parties.
The house number
Two reputable sources, two numbers. Nelson Carvalheiro gives Rua Doutor Manuel Rodrigues 43. Coimbra Coolectiva, the local title, gives 39.
Unlike the address conflict at A Cozinha da Maria, where two sources name two different streets, this one is trivial in practice: four doors on the same short street in the flat lower town. Walk the block and read the signs.
We print 43 because Carvalheiro’s write-up is the more detailed of the two and names dishes, which suggests a visit rather than a list. That is a judgement about which source was closer to the building, not a verification.
The restaurant is cited as having a website at duxrestaurante.com. We have not independently confirmed what is on it, so treat it as a lead rather than a source: if it carries current hours and a menu, it is the best available answer to everything this page cannot tell you.
Neither source gives a telephone number, which in a restaurant that takes bookings is an odd gap. If you want to reserve, the website is the route; if it is not working, treat the place as a walk-in and arrive early.
How to use it
Petiscos change how you order and how much you spend, and it is worth being deliberate about both.
Order in waves, not all at once. Three plates for two people, then decide. The mistake visitors make is ordering six dishes at the start, which arrives simultaneously and turns a long dinner into a scramble.
Share everything. A table of petiscos is a single conversation with plates in the middle, and ordering a dish each defeats the format.
Watch the bill. Small plates add up faster than a main course does, and no price band is published for this restaurant — not by either source. The mid-range assumption here comes from the style of the place rather than from a published figure, and you should ask rather than assume.
Go at Portuguese hours. Dinner service in Coimbra fills from about 20:30 and the student population pushes it later still in term time. If you want a table without waiting, arrive at the start of service rather than at the peak of it.
And do not treat the bread and olives on the table as free. The couvert is charged for everywhere in Portugal and may be sent back without offence.
Where it sits in the city
The Baixa holds the densest cluster of restaurant addresses in Coimbra, and Dux sits inside it alongside Solar do Bacalhau on Rua da Sota, Zé Neto on Rua das Azeiteiras and Adega Paço do Conde. All of it is flat and all of it is within five minutes on foot.
What Dux does that its neighbours mostly do not is contemporary. The lower town’s strength is traditional cooking — salt cod, goat, grilled meat, jug wine — and if you are eating in Coimbra for several nights you will want one evening that is not that. The other candidate is Refeitório da Baixa on Terreiro da Erva, banded higher.
For a drink and small plates rather than dinner, Fangas Mercearia Bar occupies the grocery-bar end of the same idea, up on the edge of the Alta.
Coming down from the university, this quarter is where the Alta to Baixa descent finishes, which makes it the obvious end to a day of monuments.
A practical sequence that works: the university in the morning, the Sé Velha at midday, down through the Arco de Almedina in the afternoon, and a table of small plates down here at eight. You will have gone from the twelfth century to a contemporary kitchen in four hundred vertical metres of walking.
The verdict
The most dependable ordering decision in the lower town, at an address nobody has priced.
Go if you want to eat several things rather than one, if you are two or four rather than a large group, and if you want a dinner that is recognisably modern without leaving the historic centre. The açorda alone justifies the table.
Do not go if you need the bill to be predictable. Small plates and no published prices is the combination most likely to produce a surprise, and asking as you order is the only defence.
Do not go for a Coimbra speciality either. This is contemporary Portuguese cooking rather than regional; for what actually belongs to this city and this region, read what to eat in Coimbra and then decide where the regional evening goes.
One last practical note. If the door here is closed, or the room is full, you are inside the densest restaurant cluster in the city and a minute from four alternatives. That is the standing advantage of eating in the lower town, and it applies every night of the week.