Sabaki is a modern, elegant, cross-platform Go/Baduk/Weiqi board and SGF editor for a more civilized age. It's free, open source and uses web technology based on Electron.
Sabaki offers a variety of board markup tools, including the SGF 4-compliant line and arrow tool. Annotate your positions and moves, set hotspots in your favorite games, write reviews in Markdown. Sabaki also supports SGF game containers, saving and reading multiple games within one file.
Score your games using Chinese or Japanese rules. When scoring, Sabaki automatically guesses which stones are dead using a simple heuristic. Of course you can overrule the status of each group.
Next time you don't need to go through a game from the beginning when someone says, 'Did you see the divine move at L11?' With Sabaki you can find the move instantly simply by activating find mode and clicking on the right spot on the goban.