In Japan the question is answered before it is asked, the beer arrives with the bowl or it does not arrive at all, and the pairing is so fixed that a rich ramen without a cold lager beside it reads as incomplete. But the question deserves the walk-around, because the bowl's architecture, hot, salty, fatty, intense, supports more than one answer, and the drinks list has its own opinions.
The case for beer
Lager is the classical answer and the physics backs it. Carbonation scrubs the palate, the cold resets the mouth against a soup that lands hot, and the mild bitterness stands up to salt without competing with the stock. A rich tonkotsu is the pairing beer was built for, each mouthful of soup answered by a swallow that clears the stage for the next, and the mechanism is the same one behind the lager-and-fried-chicken habits of every culture on earth. Our Sapporo and Asahi cover the position, and with a bowl high on the chilli ladder, a sixteen, say, the cold beer is less a pairing than a safety system.
The case for sake
Sake's argument is different, it is not contrast but kinship. Sake is brewed from rice and water, ramen soup is built on water and seasoned from grain, soy, miso, and the two share a softness that wine's acid refuses. Hot sake with a miso bowl is the match the northern winter proved, warm answering warm, and cold sake with a lighter bowl keeps the meal's temperature register even, the approach the omakase piece takes with the course menu. The sake guide on this site holds the details, when warm, when cold, what nama means, and the staff pour both all night for tables that want the fuller argument.
The highball and the outsiders
The whisky highball, soda-cut and ice-cold, has reclaimed its old seat in Japan as the izakaya pour, and it earns it beside ramen on the same scrubbing physics as beer with an adult edge. Green tea is the quiet professional, the free-flow pot cuts fat and answers heat, and it is the correct companion for a working lunch and for anyone climbing the chilli ladder on a weekday, tea does not impair the 2pm meeting. And for the top of the ladder, the kitchen's honest advice is older than any drinks list, milk, the capsaicin dissolves in fat, and the article on the chilli scale explains why water makes it worse.
The rule under the rules
Every real pairing rule reduces to one instruction, drink what makes the next mouthful welcome. The beer camp and the sake camp both satisfy it, the highball bridges, and the tea keeps the ladder honest. Order the bowl first, decide the drink second, and when in doubt tell the staff what you are eating, the answer arrives with the first ladle.
What not to order
The short blacklist is shorter than people fear. Big red wine fights the bowl, tannin against salt is a quarrel neither wins, and anything sweetened, most sodas included, turns the soup's salt into a chemical experiment. Milk belongs to one job only, the top of the chilli ladder, where its fat dissolves what the water cannot, and outside that emergency it dulls the bowl. Water is not the enemy the internet claims, it is neutral, but it is also nothing, and a meal built on a half-day soup deserves better than nothing beside it. Beyond those three, the field is open, and the rule from the last paragraph keeps ordering honest.