# XI: A Chess Problem explained — The Big Four

> Chapter companion for The Big Four by Agatha Christie.

## What happens

Poirot and Hastings dine with Inspector Japp, who discusses the mysterious death of American chess champion Gilmour Wilson during a match against Dr. Savaronoff. Poirot deduces that Wilson was electrocuted via a rigged chess piece and table, orchestrated by the Big Four. He identifies the niece Sonia Daviloff as an agent and the servant Ivan as Number Four, leading to a chase.

## Themes in this chapter

### Global Criminal Conspiracy

The Big Four orchestrate Wilson's murder as part of their criminal network, with Number Four and Sonia Daviloff as agents.

### Intelligence and Deduction

Poirot uses his 'little grey cells' to deduce the electrocution method and identify the culprits, contrasting with Japp's initial theories.

### Deception and Disguise

Number Four assumes multiple identities (Ivan, asylum attendant, etc.) and the murder is disguised as heart failure using a rigged chess set.

## Character check-ins

### Hercule Poirot

Dines with Hastings and Japp; deduces the murder method involving an electrified chess piece and links it to the Big Four.

### Captain Hastings

Narrates the chapter; discusses the case with Poirot and retrieves a chess book for him.

### Inspector Japp

Joins Poirot and Hastings at dinner; shares details of Wilson's death and suspects poison meant for Savaronoff.

### Gilmour Wilson

American chess champion who dies suddenly during a match; victim of electrocution via a rigged chess piece.

### Dr. Savaronoff

Russian chess champion; opponent in the match; reluctant to play due to fear of the Big Four.

### Number Four

Identified as the servant Ivan; master of disguise and orchestrator of the murder plot.

## Key lines

> I’ve been up north—that’s why. How are things with you? Big Four still going strong—eh?

Japp asks Poirot if the Big Four is still active.

_Japp's casual inquiry about the Big Four._

> Wilson was sound as a bell—no trace of heart trouble. His death is quite inexplicable.

Wilson had no known heart issues, making his sudden death suspicious.

_Japp explains the mystery to Poirot._

> I don’t believe the poison was meant for Wilson—it was meant for the other man.

Japp theorizes that Savaronoff was the intended target.

_Japp's initial theory about the murder._

> Wilson was not poisoned, he was electrocuted. A thin metal rod passes up the middle of one of those chessmen.

Poirot reveals that Wilson was killed by an electric current through a modified chess piece.

_Poirot's deduction of the murder method._

> I strongly suspect that Ivan is none other than the famous Number Four.

Poirot identifies the servant Ivan as the master criminal Number Four.

_Poirot's revelation about Ivan's true identity._

## Links

- HTML: https://www.betterreads.online/discover/the_big_four_se/chapters/xi-a-chess-problem
- Book: https://www.betterreads.online/discover/the_big_four_se
- All chapters: https://www.betterreads.online/discover/the_big_four_se/chapters