Do you know what a soduku is? It's a puzzle game involving numbers. Each 3x3 grid must be filled with the numbers 1-9. Then each 9x9 grid must be filled with 1-9 and each column and row can only have 1-9 appear once.
Seppuku is the honorable way for a samurai to commit suicide. They do it to avoid capture or if they brought disgrace to their family.
Samurai do not commit harikari because they're not happy with their life.
So kill yourself in another way. Plus I don't think you'll be able to complete the ceremony because after slicing your abdomen you need someone else to behead you to complete the ceremony.