The great Meireki Fire took place in January 1657. The fire was named after the Imperial Era name, "Meireki", which was being used at that time. (Imperial Era names are usually changed whenever a new Emperor is crowned, but there are other reasons why it might be changed, such as a great event or a terrible catastrophe. After the Meireki fire, the Imperial Era name was changed to "Manji")
The fire broke out on the 18th day of the new year, in the Hongo district near the center of Edo. There are various legends about how the fire got started, but since it was a very cold winter's day and the north wind was blowing furiously through the city, perhaps someone stoked up the fire in their house a bit too high, trying to keep warm, and a gust of wind set some clothes or furniture on fire.
Whatever the cause, once the fire got started, the strong winds caused it to spread quickly. Several months of dry weather had made all of the buildings in the city as dry as a tinderbox, and the flames swept quickly from street to street, trapping thousands of people in their homes. By the time the people of Edo realized what was happening, and were able to organize fire-fighting efforts, the fire had already leapte across both the Sumida river and Nihonbashi canal, and was burning through the blue-collar residential districts of Fukagawa and Kyobashi. The flames raged through the night, and most of the people who died in the blaze perished on that first day.
At around midday on January 19th, the wind shifted and the flames veered away from the shores of the bay toward the center of the city once again. The blaze swept toward Edo Castle, and although the fire-fighters managed to save the castle itself, several towers on the outer wall were burned to the ground. The flames also raged through the manors and residences of daimyo and lesser samurai, causing extensive damage but not quite as many deaths as on the first day.
By January 20th, the fire had at last been contained, but the ruins of the city continued to smoulder for days. It wasn't until January 24th that a huge team of government workers and samurai were able to begin collecting the piles of bodies that lay dead in the streets. The corpses were carried by boat to a large field near Ryogoku bridge, where huge pits were dug and the bodies were buried. Naturally, it was impossible to identify most of the dead corpses, so rather than try to hold individual funerals, an army of monks was brought in to the city from all the temples in the surrounding area, to say prayers for each of the dead townspeople as their bodies were placed in the pits. A large memorial hall was built over the mass graves, and it was named the Eko-In , or "Temple of Prayer for the Dead". Nobody knows exactly how many people died, but it may have been as many as 200,000, or half of the city's population.
It took nearly two years to rebuild the city, but by 1660 the population had recovered to its previous level and the city had been rebuilt according to a plan that would help contain future fires. The main streets were widened and more canals were dug in the central areas of the city to serve as firebreaks. In addition, new laws were passed, such as the rule that forced all lumber yards to be moved to the Kiba district.