Sangaku Journal of Mathematics Published by the VUZF University of Finance, Business and Entrepreneurship, Sofia, Bulgaria About this Journal   |   Editorial Board  |   Instructions for Authors   |   Review Process   |   Links ISSN 2534-9562 Editors-in Chief: Hiroshi Okumura, Professor, Ph.D. Maebashi Gunma, 371-0123, Japan e-mail: hokmr@protonmail.com Sava Grozdev, Professor, DSc, VUZF University of Finance, Business and Entrepreneurship, Sofia, Bulgaria e-mail: sava.grozdev@gmail.com Volume 2 (2018) Giovanni Lucca, A Note on a Pappus Sangaku Problem and a Family of Integer Sequences, pp.1-2. Hiroshi Okumura, A note on a problem involving a square in a curvilinear triangle, pp.3-5. Problems 2018-1, p.6 Volume 1 (2017) Hiroshi Okumura, Japanese mathematics, pp.1-6. The paper is reprinted from "Symmetry: Culture and Science",Volume 12 (1-2) 79-86 (2001) with permission from the publisher. Problems 2017-1, pp.7-10. Problems 2017-2, pp.11-12. Francisco Javier García Capitán, Solution to 2017-1 Problem 1, pp.13-15. Yasuo Kanai and Hiroshi Okumura, A three tangent congruent circle problem, pp.16-20. Supplementary material: animation.gif Problems 2017-3, pp.21-23. Hiroshi Okumura, Configurations of congruent circles on a line, pp.24-34. Hiroshi Okumura, Theorems on two congruent circles on a line, pp.35-38. Hiroshi Okumura, A note on the problems involving congruent circles in Tenzan Kaitei, pp.39-41. Hiroshi Okumura, Haga's theorems in paper folding and related theorems in Wasan geometry Part 1, pp.42-56.