This is because the Kinki region satisfied ideal conditions for producing delicious Udon noodles as follows: (1) lots of areas in this region such as Harima and Kawachi have produced high quality wheat since the period earlier than the modern age, (2) in contrast to the Kanto region where hard water was mainly supplied because of volcanic ash soil peculiar to the loamy layer of the Kanto district, the ground water pumped up in the Kinki region was soft water enjoying good compatibility with Konbu.
これは近世以前より近辺には播磨や河内など良質のコムギ産地が多かったこと、関東ローム層による火山灰土の影響で硬水が主となる関東地方とは異なり、近畿地方から採れる地下水は軟水であったためコンブとの相性が良かったことなど、美味しいうどんを作るのに最適な条件であったことが挙げられる。