The Sudoku Trick All Expert Solvers Know

Cracking The Cryptic

29 Aug 201917:53

EducationalLearning

32 Likes 10 Comments

TLDRIn this episode of 'Cracking the Cryptic,' the host dives into solving Tuesday's New York Times Hard Sudoku. The video outlines strategies for tackling the puzzle, emphasizing the importance of pencil markings and focusing on open flanks within 3x3 boxes. The host skillfully navigates through the logic, using techniques like identifying numbers that can only go in specific positions and using patterns to eliminate possibilities. The session is an insightful guide for those looking to improve their Sudoku-solving skills, showcasing a blend of strategy and methodical elimination to reach the solution.

Takeaways

🧩 The New York Times Hard Sudoku is a favorite among the variety of Sudoku puzzles available in national newspapers.
🤖 All Sudoku puzzles in daily newspapers are generated by computer algorithms, with the New York Times' algorithm being one of the better ones.
📝 For beginners, it's recommended to start by populating the grid with pencil marks, scanning rows, columns, and boxes for possible number placements.
🔍 Identifying areas in 3x3 boxes where a number can only go in exactly two positions is a useful starting strategy.
🎯 Focusing on open flanks within 3x3 boxes is a key technique encouraged by the New York Times puzzles.
🚫 Using pencil marks to track possible numbers helps in eliminating options and identifying where numbers can or cannot go.
🔄 Spotting patterns and interactions between numbers across different 3x3 blocks is crucial for advancing the solve.
🔢 When a number is placed, it can trigger a chain of deductions in related rows, columns, and boxes.
🌟 Advanced solving techniques include recognizing X-shaped patterns and using them to eliminate possibilities in columns or rows.
📈 Progress in the puzzle can be accelerated by continuously updating and refining pencil marks as new numbers are placed.
🏆 The goal is to methodically fill in the grid using logic and deduction, ultimately completing the puzzle.

Q & A

What is the main topic of the video?
-The main topic of the video is solving the New York Times Hard Sudoku puzzle.
Why does the speaker recommend the New York Times Hard Sudoku?
-The speaker recommends the New York Times Hard Sudoku because its algorithm is one of the better ones among the daily newspaper Sudoku puzzles, as they are all created by computer.
What is the first step in solving the puzzle according to the speaker?
-The first step is to go around the grid and populate it with pencil marks, scanning the rows, columns, and boxes to identify areas where a number can only go in exactly two positions in a 3x3 box.
What is a key strategy for solving New York Times Sudoku puzzles?
-A key strategy is to focus on open flanks within 3x3 boxes, looking for cells that are completely open and aligned in the same row or column.
How does the speaker use pencil marks to identify possible numbers for a cell?
-The speaker uses two types of pencil marks: one that identifies two positions in a 3x3 box where a number can go, and another that indicates a cell can only be a specific number or two possible numbers.
What happens when the speaker places an 8 in a certain cell and realizes it takes the position of a 4?
-When the speaker places an 8 in a cell and realizes it takes the position of a 4, they can then deduce that the remaining cell in that row must be a 4, which helps to further solve the puzzle.
How does the speaker ensure they are following the logic correctly while solving the puzzle?
-The speaker ensures they are following the logic correctly by carefully observing the interactions between numbers in rows, columns, and 3x3 boxes, and by double-checking their pencil marks and deductions.
What is the significance of the 'X shape' of numbers the speaker refers to?
-The 'X shape' of numbers is a pattern that helps to eliminate possibilities for where certain numbers can be placed, allowing the speaker to make more definitive placements in the grid.
How does the speaker handle mistakes while solving the puzzle?
-The speaker handles mistakes by carefully reviewing their steps and logic, acknowledging the error, and correcting it to continue solving the puzzle accurately.
What advice does the speaker give to those who are new to solving Sudoku puzzles?
-The speaker advises those who are new to pay close attention to the techniques shown, such as using pencil marks and focusing on open flanks within 3x3 boxes, and encourages them to practice these methods to improve their solving skills.

Outlines

00:00

🧩 Introduction to Solving the New York Times Sudoku

The speaker begins by introducing the video's focus on solving the New York Times hard Sudoku puzzle. They mention that while all Sudoku puzzles in national newspapers are computer-generated, the New York Times has one of the better algorithms for creating puzzles. The speaker recommends this puzzle for daily practice, especially in the absence of handcrafted puzzles. They proceed to explain the initial step of solving the puzzle, which involves scanning the grid and making pencil marks to identify potential numbers that can be placed in specific positions based on the rows, columns, and 3x3 boxes. The speaker also highlights the importance of focusing on open flanks within the 3x3 boxes to make progress in the puzzle.

05:01

🔍 Advanced Techniques for Identifying Numbers

The speaker delves into more advanced techniques for solving the Sudoku puzzle. They discuss the importance of recognizing patterns and using logic to deduce where numbers must be placed. The speaker uses the example of identifying open flanks in 3x3 boxes and how these can help determine the possible locations for certain numbers. They also explain the concept of 'pencil marking' and how it can be used to track potential number placements and eliminate options. The speaker demonstrates how these techniques can be applied to make progress in the puzzle, showing how identifying certain numbers in one area can impact the possibilities in other parts of the grid.

10:03

📝 Refining the Pencil Marking Method

The speaker continues to elaborate on the pencil marking method, showing how it can be refined to make more accurate deductions. They explain how removing a pencil mark for a number that has been placed elsewhere in the grid confirms the placement of another number in a different location. The speaker uses this technique to place several numbers in the puzzle, demonstrating how it can lead to significant progress in solving the puzzle. They also discuss the importance of being careful and methodical when making these deductions to avoid mistakes.

15:05

🎯 Final Steps and Wrapping Up the Puzzle

In the final part of the video script, the speaker wraps up the puzzle-solving process by placing the remaining numbers in the grid. They continue to use the pencil marking method and logic to deduce the final placements, showing how certain numbers can be eliminated from consideration in specific squares. The speaker emphasizes the satisfaction of seeing the puzzle come together and encourages viewers, especially those new to Sudoku, to practice these techniques. They conclude by inviting viewers to subscribe for more content on solving Sudoku puzzles.

Mindmap

Keywords

💡Cracking the Cryptic

The title of the video series, 'Cracking the Cryptic' refers to the process of solving complex puzzles, specifically Sudoku in this context. The theme of the video revolves around providing strategies and techniques for tackling difficult Sudoku puzzles, particularly those featured in the New York Times.

💡New York Times Hard Sudoku

A specific type of Sudoku puzzle featured in the New York Times newspaper known for its difficulty. These puzzles are algorithmically generated, and the video focuses on strategies for solving them, suggesting that they are among the better puzzles available due to the quality of the algorithm used.

💡Pencil Marks

A technique used in Sudoku to temporarily mark possible numbers in cells, aiding in the logical deduction process. Pencil marks are used to scan rows, columns, and boxes to identify where a number can only go, and they are particularly useful for tracking possibilities in 'three by three' boxes within the grid.

💡Three by Three Boxes

A reference to the 3x3 subgrids within the larger 9x9 Sudoku grid. These smaller boxes are key to the solving process as they help to limit the possible locations for numbers, which is a fundamental Sudoku solving strategy.

💡Open Flanks

A term used in the context of Sudoku to describe cells within a 'three by three' box that are empty (do not contain any numbers) and are aligned either in the same row or column. Identifying open flanks is a strategy that helps to narrow down the possible locations for numbers, particularly when combined with pencil marks.

💡Pencil Mark Types

Refers to the different ways of marking possible numbers in cells with pencils during the Sudoku solving process. The video mentions two types of pencil marks: one that indicates a number can only go in two positions within a 3x3 box, and another that signifies a cell can only be a specific number or another.

💡Solving Strategy

A systematic approach or method used to solve Sudoku puzzles. The video outlines a specific strategy that involves identifying patterns, using pencil marks, focusing on open flanks, and deducing the placement of numbers based on the rules of Sudoku.

💡Software

Refers to the digital tools or applications used to play or solve Sudoku puzzles. In the context of the video, software is mentioned as a way for viewers to engage with the puzzles being discussed, since the New York Times does not have an archive for past puzzles.

💡X-Wing Technique

An advanced Sudoku solving technique that involves looking for a specific number that appears in only two cells in two different rows and the same two cells in two different columns, forming an 'X' shape. This pattern helps to eliminate the possibility of that number appearing in other cells in the rows or columns, aiding in solving the puzzle.

💡Forcing Numbers

A term used in Sudoku solving to describe the process of logically deducing where a number must be placed based on the existing numbers and rules of the game. This often involves using the elimination method to narrow down the possibilities for a particular number within a row, column, or 3x3 box.

💡Pencil Mark Interactions

Refers to how pencil marks can influence each other within the Sudoku grid. When a number is placed, it can affect the possible locations for the same number in other parts of the grid, leading to further deductions and placements.

Highlights

The New York Times hard Sudoku is recommended for daily puzzle enthusiasts.

The NYT Sudoku algorithm is considered one of the better ones among computer-generated puzzles.

The presenter uses a methodical approach to solving the puzzle, suitable for beginners.

Pencil marks are used to identify numbers that can only go in two positions within a 3x3 box.

Focusing on open flanks within 3x3 boxes is a key strategy for solving NYT Sudoku.

The presenter demonstrates how to use the elimination of numbers in a box to deduce possible positions.

The importance of recognizing patterns, such as X-shapes, for eliminating possibilities is emphasized.

The presenter explains how to use pencil marks to track potential positions for specific numbers.

A technique for identifying 'one-line pairs' is introduced to fill in numbers in a row.

The presenter illustrates how to use the interaction of numbers in different blocks to deduce placements.

The process of 'unwinding' pencil marks to confirm a number's position is explained.

The presenter discusses the strategy of filling in numbers based on the available positions in a 3x3 block.

The importance of checking rows and columns to ensure no duplicates is highlighted.

The presenter demonstrates how to use the process of elimination to fill in the remaining numbers.

The presenter concludes by summarizing the techniques used and encourages viewers to apply them.

The video provides a link to the presenter's software for those who want to try the puzzle.

The New York Times does not have an archive for their puzzles, necessitating the use of alternative software.

Transcripts

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