This book constitutes the refereed proceedings of the Thailand-Japan Joint Conference on Computational Geometry and Graphs, TJJCCGG 2012, held in Bangkok, Thailand, in December 2012.
The 15 original research papers presented were selected from among six plenary talks, one special public talk and 41 talks by participants from about 20 countries around the world. TJJCCGG 2012 provided a forum for researchers working in computational geometry, graph theory/algorithms and their applications.

Operators which Preserve Reversibility.- Colored Quadrangulations with Steiner Points.- On Universal Point Sets for Planar Graphs.- On Non 3-Choosable Bipartite Graphs.- Edge-disjoint Decompositions of Complete Multipartite Graphs into Gregarious Long Cycles.- Affine Classes of 3-Dimensional Parallelohedra - Their Parametrization.- On Complexity of Flooding Games on Graphs with Interval Representations.- How to Generalize Janken - Rock-Paper-Scissors-King-Flea.- Spanning Caterpillars Having at Most k Leaves.- GDDs with Two Associate Classes and with Three Groups of Sizes 1, n, n and ¿1 < ¿2.- The Number of Diagonal Transformations in Quadrangulations on the Sphere.- Remarks on Schur's Conjecture.- Greedy Approximation Algorithms for Generalized Maximum Flow Problem towards Relation Extraction in Information Networks.- A Necessary and Sufficient Condition for a Bipartite Distance-Hereditary Graph to Be Hamiltonian.- On Simplifying Deformation of Smooth Manifolds Defined by Large Weighted Point Sets.