Tokugawa Ieyasu, who formed his government in Edo in 1590, began preparations for his castle along with setting to work reclaiming the lower wetlands that stretched below the castle to the east. In the Minato City area, major development began of the lowlands stretching to the north-eastern area in the first half of the 17th century. Soon after, development reached the coastal area. Any work was a fight against mud and water, yet the people of the Edo Period used their wealth of knowledge and superlative technology to build the foundations of the great city of Edo in a surprisingly short time.