Giving a samurai sword its curve

Quenching in water is never a good idea for a blade and Japanese bladesmiths looked for many other ways to to temper their blades because they knew it wasn't good. Lack of resources and attempting to get metallurgical know how led to many of their techniques. Don't get me wrong they did amazing things with what they had but if they had had access to better iron/steel and modern quenching techniques and metallurgical sciences they would have done things differently. Tradition plays a extremely important part in Japanese culture but you really, really wouldn't want to use a sword made in the "traditional" manner with "traditional" materials. They were extremely brittle in no small part to poor quality iron/steel and tempering like is demonstrated in this^.

Curves upwards when hot and wet

heartbreaking thing about this part of the process is one in three would break

@metalman

Katanas were made up on a mountain somewhere in japan

Made from Dragon Scale?