Seppuku is probably the most recognizable ritual associated with the Samurai in the West, second only to Bushido. There are many essays on the ritualization of death and the causes that led a Samurai to commit Seppuku: failure in a task, dishonourable conduct, disrespect, etc.
However, in my long quest of research on Sengoku Jidai and other time periods, I have found much evidence completely debunking Bushido even being a thing in Sengoku Jidai. And since I believe that Seppuku is closely tied to Bushido, I am beginning to doubt whether or not it was actually carried out the way everyone seems to think it was. After all, the act of cutting one's belly is supposed to be an excruciatingly painful process, even if the Samurai is beheaded shortly after.
I remember reading somewhere (although I cannot find the source anymore) that Daimyo (or other high ranking Samurai), knowing that they were about to be captured and would likely face torture and slow deaths at the hands of their captors (be it a enemy clan or anything else) chose to die quickly. So, they would get a retainer to be their second, would simbolically 'cut' their bellies open with a wooden short sword (likely a wooden shoto) in a gesture resembling the cut, and then their second would decapitate them, delivering a swift and painless death.
Would anyone be as kind as to confirm this statement? Was Seppuku really a way of safekeeping one's honour through such a painful ordeal, or was it really just a swift, painless death to avoid capture?
See this thread and this thread and this thread
I don't know about torture, but as a defeated daimyō if you were at the point of seppuku, either you were captured and if you didn't commit seppuku they would just execute you anyway and allowing you to commit seppuku was a form of honor, or the situation for you is so pointless you know you'd die anyway so decided to take matters into your own hand. These men were dead anyway. Seppuku was just something to preserve their honor and status rather than being beheaded or crucified like criminals. Exchanging the commander's life via seppuku in return for the lives of his family and/or subordinates was also a common treaty clause.
As mentioned in the linked threads, there were cases of seppuku for other reasons, like as a protest or in loyalty following one's master (something deemed incredibly wasteful by the Tokugawa Shogunate who outlawed it). We are sure these happened. We should however consider them the much rarer form of seppuku, and so were more notable.
Yes there was (usually) supposed to be a second to lop off the head quickly. As for cutting only as a symbol, that seemed to have taken hold in the peaceful mid-Edo, especially for more lower-class samurai. However, we're pretty sure it was done "properly", as in with a wakizashi, prior to the mid-Edo and during the Bakumatsu and early Meiji.
Also there are many descriptions of much more painful accounts, with no seconds, and/or doing multiple cuts.