Zero Point Breakthrough: First Edition is a technique created by Giotto and later used by the Timoteo and Tsunayoshi Sawada. It takes advantage of the user being in Hyper Dying Will Mode to create ice that can seal away Dying Will Flames and can only be melted by strong Dying Will Flames.
The ice created by this technique cannot be melted using ordinary means, as any energy that comes in contact with it gets turned into negative energy. It can only be melted using Dying Will Flames.
When Tsuna uses this technique, the Roman Numeral "I" appears on his X-Gloves to show that it was a technique created by Giotto, Vongola Primo.