Ki (chi) - As in Yonggi (courage) or Kihap (scream).
The Chinese symbol for Chi 氣 is made up of two characters, (米) rice, and (汽) steam/vapor. The idea is "steam coming off of hot rice". We often think of Chi as energy. And in the west we tend to look at Chi as an external showing (screaming, hitting or getting hit hard, breaking blocks, boards, etc...). Or we tend to think of it as soft sustaining energy, as in Tai Chi. But when we only limit Chi to these two areas, we're missing the entire point.
Growing up in the North, where it actually snows, I'm fairly familiar with seeing my breath. Now let me remind you that Chi is steam coming off of rice. Does my breath look similar? Yes. Chi is BREATH. Because of this I want to tell you that you can kihap without screaming. grin emoticon Yes. Your kihap is not necessarily the sound you make, but the energy that comes from your danjun while you breathe and exhale.
This is why in martial arts we need to always train Weh Gong (external power), Neh Gong (internal power), and Shim Gong (spiritual power). These 3 are all facets of Chi. And never forget... if you're not breathing, your dead.
All calligraphy done by Master Dan Bernardo