"The robot broke the child's finger," Sergey Lazarev, Moscow Chess Federation President, told Tass news agency. "This is of course bad."

A video shared on social media shows the robot taking one of the boy's pieces. The boy then makes his own move, and the robot grabs his finger.

Four adults rush to help the boy, who is eventually freed and ushered away.

Mr Lazarev said the machine had played many previous matches without incident.

The boy was able to finish the final days of the tournament in a cast, Tass reports.

Step 1

Whisk hoisin sauce, vinegar, soy sauce, hot sauce, sesame oil, grated ginger, garlic, brown sugar, salt, and pepper together in a large mixing bowl.

• Step 2

  Cut skirt steak crosswise into about 4 or 5 smaller pieces. Transfer steak into marinade and toss until all pieces are evenly coated. Cover with plastic wrap. Refrigerate; marinate at least 2 hours and up to 12 hours.

• Step 3

  Line a baking pan with paper towels. Transfer pieces of steak to the paper towels and mop off some of the marinade.

Step 1

Preheat the grill for high heat.

• Step 2

  In a bowl, mix the ground beef, ranch dressing mix, egg, crushed crackers, and onion. Form into hamburger patties.

• Step 3

  Lightly oil the grill grate. Place patties on the grill, and cook 5 minutes per side, or until well done.

Step 1

Place ginger, garlic, onion, brown sugar, fish sauce, vegetable oil, soy sauce, coriander, cumin, turmeric, and cayenne pepper into a mixing bowl; whisk into a smooth marinade.

• Step 2

  Bruise lemon grass by hitting it lightly several times with the back of a large chef's knife; mince the lemon grass and add to the marinade.

• Step 3

  Cut beef sirloin into strips about 2 1/2 inches long and 1/8 inch thick. Thoroughly mix the beef into marinade until all beef strips are completely coated, about 1 minute. Cover bowl with plastic wrap and marinate in refrigerator for 2 to 4 hours.

• Step 4

  Preheat an outdoor grill for high heat and lightly oil the grate.

• Step 5

  Remove beef from marinade and shake off excess marinade. Thread 1/4 the meat onto each metal skewer.

• Step 6

  Arrange skewers on the preheated grill and cook until the meat stops sticking to the grill, about 1 to 2 minutes. Flip skewers over onto other side and cook until meat is well browned and shows grill marks, 2 to 2 1/2 minutes. Turn onto first side again and cook until meat is still slightly pink, 2 more minutes. Transfer to a platter and let skewers rest about 2 more minutes before serving.