• Journal for History of Mathematics
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• v.33 no.6
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• pp.315-325
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• 2020

In this study, how Choi Seok-Jeong made Hadoguodo is presumed. Choi SeokJeong's Hadoguodo does not actually reflect the Hado. But it is verified that Hadoguodo reflecting Hado can be made. In addition, it is verified that Hadoguodo can be made so that not only the sum of the nine numbers of each square are all 207 but also the sum of the nine numbers in the horizontal and vertical directions are all 207.

• Journal for History of Mathematics
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• v.28 no.2
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• pp.73-83
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• 2015

In this paper, we give answers to some interesting questions about a Confucian scholar and mathematician in the late Joseon Dynasty, CHOI Seok-Jeong(崔錫鼎, 1646-1715), who was inducted into the Science and Technology Hall of Fame (http://kast.or.kr/HALL) for his mathematical achievements in October, 2013. In particular, we discover that CHOI Seok-Jeong was able to devote his natural abilities and time to do research on mathematics, and that he frequently communicated with his friend and fellow scholar, LEE Se-Gu(李世龜, 1646-1700), who was an expert on the astronomical calendar and mathematics, based on at least 24 letters between the two.

• Journal for History of Mathematics
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• v.23 no.3
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• pp.21-31
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• 2010

A latin square of order n is an $n{\times}n$ array with entries from a set of n numbers arrange in such a way that each number occurs exactly once in each row and exactly once in each column. Two latin squares of the same order are orthogonal latin square if the two latin squares are superimposed, then the $n^2$ cells contain each pair consisting of a number from the first square and a number from the second. In Europe, Orthogonal Latin squares are the mathematical concepts attributed to Euler. However, an Euler square of order nine was already in existence prior to Euler in Korea. It appeared in the monograph Koo-Soo-Ryak written by Choi Seok-Jeong(1646-1715). He construct a magic square by using two orthogonal latin squares for the first time in the world. In this paper, we explain Choi' s orthogonal latin squares and the history of the Orthogonal Latin squares.

• 대한핵의학회:학술대회논문집
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• 1990.04a
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• pp.207-208
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• 1990

• 한국도로학회:학술대회논문집
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• 2009.11a
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• pp.69-72
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• 2009

• Journal for History of Mathematics
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• v.27 no.2
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• pp.111-125
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• 2014

Jisuguimundo is an inimitable magic hexagon devised by Choi Seok-Jeong, who was the author of GuSuRyak as well as a prime minister in Joseon dynasty. Jisuguimundo, recorded in GuSuRyak, is also known as Hexagonal Tortoise Problem (HTP) because its nine hexagons resemble a tortoise shell. We call the sum of numbers in a hexagon in Jisuguimundo a magic sum, and show that the magic sum of hexagonal tortoise problem of order 2 varies 40 through 62 exactly and that of hexagonal tortoise problem of order 3 varies 77 through 109 exactly. We also find all of the possible solutions for hexagonal tortoise problem of oder 2.

• 대한핵의학회:학술대회논문집
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• 1992.06a
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• pp.201.1-201.1
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• 1992

• Ceramist
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• v.9 no.2
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• pp.24-32
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• 2006

• Korea Information Processing Society Review
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• v.17 no.4
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• pp.77-83
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• 2010

• 대한두경부종양학회:학술대회논문집
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• 2001.05a
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• pp.78-78
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• 2001