The Nagasa of a Japanese sword describes the length of the blade.
It is found by measuring in a straight line from the back notch on the back of the habaki, called the Munemachi, right to the very tip of the blade as shown in the illustration above.
Traditionally the unit of measurement was in 'shaku' and it is still used to describe a swords length in Japan. Originally, the actual length of a single shaku varied from region to region and was based on the distance across the span of a human hand but has now been standardized to 11.9" (30.3cm).
This means that a blade that is commonly described as having a Nagasa of 28" is 2.35 shaku long.
For modern made Katana replicas, it is important to distinguish blade length from Nagasa as some manufacturers measure from the hand guard and not the munemachi as it should be measured.
At sword buyers guide, we always measure the correct, traditional way - if we were measuring from the tsuba hand guard, the blade would be approx 1" longer. As such, care should be taken to ensure that when buying a Japanese style sword that it is clear WHERE the measurement of the blade length starts from.
When it comes to selecting the right Nagasa based on your height, there are several methods to determine this, though none are 'right or wrong' as it is largely a question of personal preference. But below is a simple chart that serves as a starting point.
There are other methods for determining the ideal Nagasa here, bearing in mind that this is just a guideline.
As a rule of thumb, anyone over 6' 6" will probably be more comfortable wielding what is called an 'O-Katana' or 'great Katana' with a 33" length blade.
I hope this information on Nagasa has been helpful. To return to Samurai Sword Terminology from Nagasa, click here