this is from sudoku.com, which says all their puzzles are solvable without guessing or allowing branches... but I'm stuck.
{67}{679}{469}{57}{2}{1}{8}{3457}{347}
{1278}{178}{248}{57}{6}{3}{1457}{9}{47}
{3}{17}{5}{8}{4}{9}{6}{17}{2}
{268}{4}{2689}{3}{589}{7}{259}{258}{1}
{178}{13789}{89}{2}{589}{6}{34579}{34578}{34789}
{5}{3789}{289}{1}{89}{4}{2379}{6}{3789}
{9}{68}{7}{46}{3}{2}{14}{148}{5}
{68}{2}{3}{46}{1}{5}{479}{478}{4789}
(4}{5}{1}{9}{7}{8}{23}{23}{6}
I've just registered - I hope this is in a usable format.