Some familiar assassins pop up at the end of Shogun episode 9. But what exactly is a shinobi?

In Shōgun episode 2, wayward Englishman John Blackthorne (Cosmo Jarvis) receives one of many incoming lessons in just how hardcore his new Japanese home is. An assassin breaks into Blackthorne’s quarters at night and instead finds the mighty Lord Toranaga (Hiroyuki Sanada), who is able to kill the killer with the Anjin’s assistance.

Lady Mariko (Anna Sawai) tells Blackthorne that this female assassin was part of a dangerous sect and that she likely trained her whole life in preparation for this one assassination attempt. What Mariko is describing is a “shinobi.” Now, in Shōgun episode 9, we encounter shinobi once again in a far more tragic fashion.

Hired by the villainous regent Ishido (Takehiro Hira), several black-clad shinobi sneak into Toranaga’s supporters’ quarters in the dead of night and attack. They eventually corner Mariko, Blackthorne, and company in a store room and blow up the door, killing Mariko. But who exactly are these shinobi? Episode 9 of the official Shōgun companion podcast has a fascinating breakdown on the assassins.

“When we were looking at the assassin in episode 2, that was a good doorway into the shinobi,” series writer and researcher Caillin Puente said. “There’s so much lore about shinobi dating back to the Edo period. That’s when you start to see the image of [shinobi dressed in black]. They were a lot of different things but they were mostly spies gathering information.”

Yes, shinobi were professional spies and occasional assassins who either dressed in black or wore nondescript clothing to better blend in. If that sounds like a ninja to you then I am delighted to report that you are right on the money. The terms “ninja (or “one who is invisible”) and “shinobi” (or “one who sneaks”) are interchangeable enough that they both direct to the same page on Wikipedia.

Western audiences in the post WWII-era tend to be more familiar with the word “ninja.” For much of the Edo period and the Sengoku period that precedes it, however, these individuals were better known as shinobi. Where did shinobi come from though? The Shōgun podcast once again has the answer.

“A lot of the time they were ashigaru, who were the foot soldiers,” Puente said. “Whenever we’re seeing a big army behind Toranaga or Yabushige, the vast percentage of people there are ashigaru. When they aren’t at war they’re working for hire – they’re farmers, they’re doing whatever.”

Shōgun was willing to draw from both shinobi fact and shinobi fiction in its depiction.

“They fulfilled a lot of different roles and it became this huge mythology that’s a little bit difficult to pick apart. We definitely veer a little closer to the legend because we need them to come in at night and be this deadly, scary force.”