To read more about the basic concept of unbroken line in Chinese and Japanese calligraphy, please see part 1 of this tutorial.
An implied unbroken line between two characters appears in virtually any of the Chinese or Japanese masterpieces in either cursive (草書), semi-cursive (行書) or kana (かな) scripts. The reason for it is very simple, and it is directly related to the direction of writing Chinese calligraphy, but also Chinese aesthetics and philosophy.
Traditionally, Chinese characters are written from the top of the page to the bottom, and right to left. Then, the general rules of the stroke order, applied during writing any of the Chinese characters, follow the direction from left to right and top to bottom. Consequently, a brush in hands of a skilled calligrapher moves freely, gliding from one character to another. Both types of the unbroken line (visible and invisible) are a natural outcome of the traditional methods of writing Chinese calligraphy.
Invisible unbroken line amplifies the artistic values of calligraphy. When you look at a row of Chinese characters, connected with an invisible unbroken line, your eyes will see much more than it is written. Although the line does not exist, and the connection is only metaphysical, the calligraphy text will appear to be more expressive and richer in form. Similarly to ink painting, Chinese calligraphy is an abstract art. The beauty of both is often hidden in what is not physically sensible.
The only way to understand how and where to apply the unbroken line during writing, is through diligent studies of Chinese and Japanese calligraphy masterpieces.
Ponte Ryuurui (品天龍涙)