The Delicate Art of Negotiation is Kenji Tale 3 of 3, the last of his tales, set at Umugi Cove in Act 2. You act as Kenji's hidden bodyguard while he meets a criminal he owes money to. It rewards the Charm of Broken Barriers and 6 Leather.
Part 3 of 3 in Kenji's Tales
Part 11 of 66 in Tales of Tsushima
Kenji is in trouble near the cove entrance. He and Gon were selling food and medicine to survivors at high prices, and Gon caught him skimming the profits. Kenji says the skim went to the survivors. Ride with him to the meeting in the marsh. Kenji wants you out of sight until he speaks a code phrase. Circle the area while he talks.
Talk to Kenji. Ride with him to the meeting. Hide near the meeting spot. Protect Kenji. Talk to him afterward.
Gon has armed men hidden around the meeting. Jin quietly takes out most of them before Gon makes his move to kill Kenji. Kenji gives the signal and Jin kills Gon and the rest. Then flaming arrows rain down: Mongols were also waiting to catch Kenji. After that fight, Kenji promises to stop landing himself in these messes, and the two part ways.
Clear as many hidden henchmen as you can with stealth before Kenji gives the signal. Fewer enemies means an easier fight when the Mongols arrive.
Nattou and the Sake Seller
Nattou and the Sake Seller is Kenji Tale 2 of 3, an Act 2 side tale south of the Ruins of Old Yarikawa in Akashima. Kenji says an empty Mongol camp is ripe for looting, and it is not empty for long. It rewards the Charm of Advantage.
Servant of the People
Servant of the People is Kenji Tale 1 of 3, an Act 1 side tale at Aoi Village in Tsutsu. You find Kenji claiming to protect farmers' food from the Mongols, which of course goes wrong. It needs The Broken Blacksmith done and rewards the Charm of Well-Being I and 10 Linen.
Honor Buried Deep
Honor Buried Deep is an Azamo Bay side tale where a villager named Hyoe suspects his neighbor of meeting bandits at night. You stake out a cemetery and follow them, and the reward is a Charm of Broken Barriers.
A Thief of Innocence
A Thief of Innocence is an Act 2 tale in Umugi Cove where a mother asks you to find her missing daughter, Kuma. You question locals, trail a strange Straw Hat and raid an inn, and the reward is a Charm of Ferocity.