We walk over manholes without paying attention to them. In France, they are discreet and part of the décor. Robust and reliable, they stick to their functional role. Did you know that in Japan there are aficionados of these plates? Domestic and foreign tourists alike stop in the middle of the road to admire some of them. And for good reason, they are so attractive that they catch the eye and are worth a look.
Today, the oldest sewage outlet still in use is in Hakodate, one of the largest cities in Hokkaido Prefecture. However, the first one to be installed in Japan, in 1885, was in Tokyo. It existed until the 2000s before being replaced for safety reasons. Indeed, with the increase in car traffic and the growth of heavy goods transport, this urban equipment has evolved. Lighter and lighter but increasingly robust, it must now support a weight of twenty-five tonnes and be able to let out the pressure of water and air. It has a life expectancy of fifteen years under heavy use, but the average is thirty years. The plates are manufactured in foundries and ordered by municipalities, prefectures and electricity and gas suppliers. Today there are more than 15 million of them in Japan.
Since the 1960s, large cities have been putting their coat of arms on manholes. In the 1980s, an official from the Ministry of Construction, wishing to raise public awareness of urban hygiene, began to design the manhole covers. From now on, each municipality will have its own design and will use the manhole cover as a tourist promotion medium. For this purpose, the municipality calls upon the creativity of its officials, subcontractors or directly upon the taxpayers who send in their proposals.
Very often, the designs represent the assets of the city; a historical monument, a local speciality, emblematic animals or plants. Sometimes famous mascots adorn the round cast iron. The aesthetic diversity has attracted the attention of the local population and visitors, so that many local institutions, both public and private, have been riding the wave. Trading cards were published and a photo collection was produced. Replaced, sometimes stolen, plates are now on the second-hand market and are being sold at auction.
However, there are many technical issues involved in the manufacture of these cast iron "canvases". When cast, they must comply with a set of specifications that must respect numerous regulations in order to ensure the safety of pedestrians and the maintenance of pre-existing infrastructures. The design must not obstruct the grooves for optimal water flow or cause vehicles to skid unexpectedly.
If you are touring Japan, don't forget to look where you are walking, there may be an artistic surprise under your feet!
Marie Ebersolt