Like spaghetti bolognaise, hairy crab is not a great dish for a first date. It spits and squirts as you tear it apart, suck out the bright orange roe and poke meat out of its spindly legs. It's easy to end up wearing it - and a liberal sprinkling of saffron-coloured crab oil is not a good look. But it's delicious, and in October diners' thoughts in Shanghai and Hong Kong are focused on 'mitten crabs', as the Shanghai hairy crab is also known. This year the crabs are particularly good.
Hairy they definitely are, with distinctive golden fringes on their muddy green legs. The most famous home of the freshwater crustaceans is Yangcheng Lake near Suzhou, a 90-minute drive from Shanghai in Jiangsu province. The Mid-Autumn Festival usually marks the start of the peak season, lasting through October, when the prized females are full of roe. From late October to the end of the year, males are deemed superior.
This year Yangcheng's crop got a few days reprieve, and piles of steamed crabs were missing from many family reunion tables in the Yangtze River Delta. The Yangcheng Lake Crab Association in Suzhou announced that this year's crab fishing season was delayed until September 17, five days after the Mid-Autumn Festival. Any crafty crab farmer trying to sneak in a few early ones to catch the festival price rise would not be entitled to call them Yangcheng Lake crabs.
Traditionally, the price of crabs from this area rises 10 to 20 per cent annually, and this year is no exception. Last year, the prices of crabs, often sold in male and female pairs, with females slightly lighter than males, peaked at more than 250 yuan (HK$304) in December.
The good news, according to the crab association, is that this year's crabs are bigger and better quality than last, due to the spring drought in Jiangsu province. The Yangcheng Lake's water level dropped from two metres to 1.5 metres, which allowed more sunshine into the water, creating a better environment for the hairy crabs to mature.
Sonny Gao, proprietor of Lu-shan Framing and Interiors in Shanghai, is taking me to her favourite Shu You restaurant at 2399 Hongqiao Road near her shop. Her son Joshua, five, is much less impressed with the rows of dark green bamboo-bound live crabs than his mother. We elect to have our victim turned into ginger and onion fried crab, or jiang cong chao xie, priced at 158 yuan.
'Everyone goes for hairy crab dinner this time of year; it's traditional for Shanghai people,' says Gao, adding that she usually buys crabs in the market and steams them at home. '[It's] cheaper - and because they are very messy to eat, it's easier at home with newspaper for the shells.'
Arriving at the table 15 minutes later, the olive green shell has turned deep red and the crab has been chopped into pieces. Its modest price and lack of roe suggests this is not a prime Yangcheng specimen, but one of its less glamorous cousins. Delicious nevertheless, it's a fiddly business extracting every morsel of meat from the spiny legs and chunkier claws. Much slurping and sucking is involved and it's simplest to abandon chopsticks and dive in with your hands. A finger bowl suggests this is acceptable.
Shanghai is full of restaurants promoting hairy crab at the moment: Peninsula Shanghai's Yi Long Court restaurant has a six-course lunch and eight-course dinner menu featuring an array of crab dishes. Hong Kong-born executive chef of Chinese cuisine Dicky To has lined up saut?ed egg white with diced scallop and hairy crab meat in a crispy nest, braised imperial bird's nest soup with hairy crab roe and crab meat, steamed fillet of giant grouper with two kinds of hairy crab roe sauce, stewed Australian grain-fed beef brisket with shredded Tianjin cabbage and mung bean noodles in hairy crab sauce, and fried rice topped with hairy crab roe and yellow fungus.
The advantage of a five-star hotel is that chefs do all the messy work for you, dissecting the crab at your table, so there's no grappling with the armoury or tools traditionally supplied for extracting the meat from the shell. The full set of eight instruments would do a surgeon proud: it includes scissors, pick and small hammer.
Peninsula Shanghai food and beverage manager Teddy Leung says the bulk of hairy crabs are farmed now. 'The wild ones have all been eaten by other animals,' he explains. Nevertheless, wild mitten crabs have made their way to America and Europe, even to the River Thames outside London, where they are an invasive species and regarded as a pest.
In Hong Kong we have to make do with their cousins, but even then it's a case of buyer beware, with crab fakers reportedly bleaching underbellies to pass them off as the real thing. Always buy from a reputable supplier, Leung advises. A live crab should be tightly wrapped in bamboo straw. Check its eyes are bright and moving. 'The shell bottom and neck should be very clean - it must have hair on its neck,' he says. Bubbles coming from its mouth mean it's very fresh.
Chef To advises steaming a 200-gram crab for 25 minutes. There's no humane chilling to anaesthetise it first - it's straight into the pot for a slow, steamy death. When it changes colour and crab roe is leaking out of the now gaping mouth it's ready. Surprisingly, Leung says both male and females have roe, but he must know his subject.
Keep hairy crab recipes simple. The delicate flavour is overpowered by strong oils and tastes; it goes well with chicken stock, sweet vinegar, dried egg white and steamed bean curd. 'It's best steamed whole - the Cantonese like it with ginger and spring onion,' To says.
Hairy crab is not hazard-free - don't eat persimmon with it or a chemical reaction will give you a nasty stomach upset. For good digestion and a perfect complement to the slightly sweet crab meat, Chinese rice wine is the only drink to have with it, Leung insists.
According to the Chinese, crab is a cooling food, so drink warming ginger tea afterwards, Leung says. 'Crabs come from a cold lake, so never eat the lungs or the heart - the heart is the coldest part and you will freeze,' he adds. He says their Western chef ignored this, ate a crab heart and came down with a nasty dose of flu as a result.
Eating crabs in season is vital. 'Otherwise they are watery and not plump. They should only be eaten when there is an 'R' in the month,' To says.
This year Peninsula Shanghai not only brings the crabs to you, but takes you to the crabs. Its hairy crab package - for 2,900 yuan plus 15 per cent surcharge per room per night, based on two sharing - includes bed, breakfast and a sumptuous eight-course crab dinner for two; but the Peninsula Yangcheng Lake weekend package (8,800 yuan per room per night, plus 15 per cent, two nights minimum) goes one step further. Guests are whisked off by BMW limo with a picnic lunch for a private tour of a Yangcheng Lake crab farm. They learn about the natural habitat and behavioural patterns of crabs and choose three to take away for an eight-course crab banquet. firstname.lastname@example.org 
The steam team
Liu Yuan Pavilion (3/F, The Broadway, 54-62 Lockhart Road, Wan Chai, tel: 2804 2000)
Hong Kong Old Restaurant (B/F, Newton Hotel, 218 Electric Road, North Point, tel: 2508 1081 or 4/F, Miramar Shopping Centre, 132 Nathan Road, Tsim Sha Tsui, tel: 2722 1812)
Branches of Shanghai Min are serving hairy crab until November 30. Flagship restaurant Xiao Nan Guo is at 10/F, One Peking, 1 Peking Road, Tsim Sha Tsui, tel: 2527 8899
Hairy crab roe is being offered in several forms at Cuisine Cuisine (shop 3101, IFC Mall, Central; tel: 2393 3933)
Shang Palace at the Kowloon Shangri-La is offering hairy crabs matched with Hua Diao wine until the end of November (64 Mody Road, Tsim Sha Tsui East, tel: 2733 8754)
The Chinese Restaurant at the Hyatt Regency is offering both innovative and traditional dishes (Hyatt Regency Hong Kong, 18 Hanoi Road, Tsim Sha Tsui; tel: 3721 7788)
Hoi King Heen at the InterContinental Grand Stanford is serving hairy crab in 10 different styles until the end of November (B2, InterContinental Grand Stanford, 70 Mody Road, Tsim Sha Tsui East, Kowloon, tel: 2731 2883)
For home cooking, go to Wah Kee Wing Cheong Ho (G/F, 460 Lockhart Road, Causeway Bay, tel: 2836 6411; www.wahkeefoods.com ). This year, crabs cost from HK$590 per piece for the best, down to HK$100 for three, depending on quality. Crabs are reportedly sourced from the highest quality waters on the mainland.