An attack that relies on emotions and, more particularly, on sadness and depression. The depression allows user to drag a monstrous quantity of ki and imprison it in a sphere that they can propel and which explodes upon contact with something or someone. It's like using ki to contain ki, but the emotional containment doesn't consume ki so it is more effective. Think of it as a containment matrix powered by emotions. The emotion doesn't power the blast, it just guides the ki into the blast and contains it. It has very little power in itself, not enough to be used in more than firecrackers. Besides, relying on an emotion becomes dangerous. However, they are really good to channel ki. Emotions are just a guide and a container for ki. Anyway, emotions are way easier to manipulate than pure ki. They unfortunately don't allow intricate manipulations, The stronger the emotion, the more ki it can force out of your body. As ki generated by depression and anger is ‘heavy,’ by projecting it into the air, Ryoga (when executing the Perfect version of this technique) creates a massive sphere of ki that can decimate a whole city block. Since Ryoga is ‘emotionally hollow’ after the attack, he himself is unaffected by the blast. However, he can be distracted out of this state and thus hit by the blast too. Ryoga has also developed a technique to burry matter within his ki. Lastly, Ryouga can engulf his fists with shishi hokoudans, and not fire them.
By dragging the emotion within you, you can draw ki as well and thus annul the attack or part of it. The downside is that you fill yourself with said emotion and it often requires a release.