Blast Furnace technology, in which you 'blast' air at regular intervals into the central heating unit, was discovered at roughly the same time both in China and in Medieval Europe. The Blast Furnace might be the most important Medieval invention after capitalism. Europeans did not 'import' the technology from China, no proof to this allegation exists [as with so much other disingenuous nonsense with other European inventions]. Such historical revisionism seeks only to demean the medieval European and elevate his 'multicultural' contemporary. It is not history, and it has precious little to do with facts.

In China there arose an expanding and profitable industry in iron works, premised in part on blast furnace technology which was developed around 1000 AD – or at the same time it was created in Europe. An independent middle and upper class formed, fed by the profits of iron manufacture and sale. The Chinese economy and society was being transformed, industrialization was being created, and labour specialization employed, all due to the expansion of iron and the dynamism of its up-and-down stream markets. The Mandarins who feared a loss of control, a new power center of capitalist wealth, and social change; smashed the iron foundries and furnaces into rubbish. By 1100 not one single blast furnace or iron foundry existed in China. So much for freedom and societal improvement.

In Europe the opposite occurred. In Spain in spite of the Moslem Jihad and wanton destruction and dislocation of Christian lands in the peninsula, the 'Catalan forge' had been employed by 750 AD. Taller furnaces with a nozzle into which air was pumped greatly aided in driving the temperature high enough to forge high quality iron and steel implements. Productivity also soared as the furnaces produced more material with less slag or waste.

In central Europe, in Austria, Saxony, and along the Rhine, the Catalan forge was improved. Furnace heights in these areas reached as high as 16 feet. These larger creations produced what is termed 'malleable' iron directly from the ore and produced about 40% more iron output than the Catalan forge. Furnaces became so tall, that the use of waterpower was necessary to compress air into a stronger blast. Over the next 150 years, incremental changes accrued to the European furnace, until a true blast furnace emerged probably sometime in the 13^th century in places as diverse as Belgium and Sweden. [source]

The difference between Medieval Europe and China can hardly be underestimated. In China, technology was seen as a threat to the state. In Medieval Europe, abetted by the Church and oftentimes directly funded by the Church, technology was deployed to improve the lives of people. This cultural gap is why Europe went on to dominate the world. People in Europe viewed the world as 'knowable', workable, linear not circular, and that life had meaning. Freedom, free-will, responsibility and the need to improve, were a vital part of European Medieval culture. Such attitudes and characteristics did not exist in China, nor anywhere else in the world. This is why the China devolved and remained isolated, impoverished, remote, and backwards.