1. “Spectre of the Gun” (Season 3, Episode 6): Chekov’s description of the OK Corral and his disbelief at being a participant in the reenactment showcase his character’s innocence and youthful perspective, which is endearing to viewers.

2. “The Naked Time” (Season 1, Episode 4): Chekov’s delirium and energetic fencing display aboard the USS Enterprise highlight Koenig’s comedic timing and add a layer of humor to a tense episode.

3. “The Trouble With Tribbles” (Season 2, Episode 15): Chekov’s national pride is humorously displayed as he claims Scotch whisky was invented by a little old lady from Russia, providing a lighter moment amidst the tension with the Klingons.

4. “The Apple” (Season 2, Episode 5): The moment where Chekov shares an intimate scene with Yeoman Martha Landon showcases Koenig’s ability to portray romance and tenderness within the sci-fi context.

5. “Day of the Dove” (Season 3, Episode 7): In this episode, we see a more aggressive side of Chekov as he becomes influenced by an alien entity, showing Koenig’s versatility in portraying emotional range.

6. “Amok Time” (Season 2, Episode 1): Chekov is concerned for Captain Kirk as he faces Spock in combat on Vulcan. His unwavering loyalty shines through in this high-stakes episode.

7. “Who Mourns for Adonais?” (Season 2, Episode 2): Chekov displays courage and ingenuity when faced with the god-like being Apollo. His actions demonstrate his quick thinking and tactical skills.

8. “The Way to Eden” (Season 3, Episode 20): Chekov’s interactions with Irina Galliulin show a personal past and life beyond his role at the navigation console, adding depth to his character.

9. “A Piece of the Action” (Season 2, Episode 17): Koenig plays up Chekov’s playful curiosity about strange new worlds when he gets involved with Chicago-style gangsters on Sigma Iotia II, providing light-hearted amusement.

10. “Mirror, Mirror” (Season 2, Episode 4): Although not featuring our universe’s Chekov directly, Mirror Chekov’s attempt to kill Captain Kirk shows a darker side of the character that Koenig executes with chilling precision.