The Citroen DS is an executive car produced by the French manufacturer Citroen between 1955 and 1975. Styled by Italian sculptor and industrial designer Flaminio Bertoni, the DS is known for its aerodynamic futuristic body design and innovative technology, including a hydropneumatic self-levelling suspension. The DS advanced achievable standards in automobile ride quality, handling, and braking.[2] Citroen sold nearly 1.5 million D-series during the model's 20-year production run. The DS came in third in the 1999 Car of the Century competition, recognizing the world's most influential auto designs, and was named the most beautiful car of all time by Classic & Sports Car magazine. After 18 years of development in secret as the successor to the venerable Traction Avant, the DS 19 was introduced on 5 October 1955 at the Paris Motor Show. The car's appearance and innovative engineering captured the imagination of the public and the automobile industry almost overnight. In the first 15 minutes of the show 743 orders were taken, and orders for the first day totalled 12,000.[4] Far from being just a fascinating technology in search of a purpose, contemporary journalists were effusive in noting how the DS dramatically pushed the envelope in the ride vs. handling compromise possible in a motor vehicle. To a France still deep in reconstruction after the devastation of World War II, and also building its identity in the post-colonial world, the DS motor car was a symbol of French ingenuity.[citation needed] It defied virtually every automotive design convention of that era. It also posited the nation's relevance in the Space Age, during the global race for technology of the Cold War.[original research?] Structuralist philosopher Roland Barthes, in an essay about the car, said that it looked as if it had "fallen from the sky". Outside of France, the car's radical and cosmopolitan design appealed to non-conformists. An American advertisement summarised this selling point: "It takes a special person to drive a special car".[citation needed] The DS was historically significant for many reasons, one being that it was the first mass production car with front power disc brakes. It also featured hydropneumatic suspension including an automatic levelling system and variable ground clearance, power steering and a semi-automatic transmission, and a fibreglass roof which reduced weight transfer.[citation needed] Inboard front brakes (as well as independent suspension) reduced unsprung weight. Different front and rear track widths and tyre sizes reduced the understeer typical of front-engined and front-wheel drive cars. In conventional cars, hydraulics are only used in brakes and power steering. In the DS they were also used for the suspension, clutch and transmission, although the later ID19 did have manual steering and a simplified power braking system. At a time when few passenger vehicles had independent suspension on all wheels, the application of the hydraulic system to the car's suspension system to provide a self-levelling system was an innovative move. This suspension allowed the car to achieve sharp handling combined with very high ride quality, frequently compared to a "magic carpet". The system used – hydropneumatic suspension – was pioneered the year before, on the rear of another car from Citroen, the top of range Traction Avant 15CV-H. In a hydropneumatic suspension system, each wheel is connected, not to a spring, but to a hydraulic suspension unit consisting of a sphere of about 12 cm in diameter containing pressurised nitrogen, a cylinder containing hydraulic fluid screwed to the suspension sphere, a piston inside the cylinder connected by levers to the suspension itself, and a damper valve between the piston and the sphere. A membrane in the sphere prevented the nitrogen from escaping. The motion of the wheels translated to a motion of the piston, which acted on the oil in the nitrogen cushion and provided the spring effect. The damper valve took place of the shock absorber in conventional suspensions. The hydraulic cylinder was fed with hydraulic fluid from the main pressure reservoir via a height corrector, a valve controlled by the mid-position of the anti-roll bar connected to the axle. If the suspension was too low, the height corrector introduced high-pressure fluid; if it was too high, it released fluid back to the fluid reservoir. In this manner a constant ride height was maintained. A control in the cabin allowed the driver to select one of five heights: normal riding height, two slightly higher riding heights for poor terrain, and two extreme positions for changing wheels. [The correct term oleopneumatic (oil-air) has never gained widespread use. Hydropneumatic (water-air) continues to be preferred overwhelmingly.] The DS did not have a jack for lifting the car off the ground. Instead, the hydraulic system enabled wheel changes with the aid of a simple adjustable stand

Kanagawa pref (at Kamakura). Another cover of Kanagawa prefecture. A gull, a ginkgo leaf, a gold-banded lily, which are the symbol of the prefecture, are drawn.