But in each game I played on Jocly, it quickly beat me by moving out a piece that checks the King along a diagonal with four of my pieces between the King and the enemy piece.
That is no bug, just implementation of the rules. Tenjiku Shogi has some pieces pieces that can jump over arbitrary many others to capture. By moving a Pawn out of the way such a piece (the 'Vice General') immediately threatens a smothered mate. There is only one way to prevent that mate, covering the mating square with your Soaring Eagle.
There is an article on Tenjiku Shogi that describes how the pieces move. What would be the point of duplicating that information? Knowing how the pieces move might be a necessary condition, but it is not a sufficient one to become a good Tenjiku-Shogi player. If you don't know any opening theory, you will be slaughtered in a few moves by someone that does.
That is no bug, just implementation of the rules. Tenjiku Shogi has some pieces pieces that can jump over arbitrary many others to capture. By moving a Pawn out of the way such a piece (the 'Vice General') immediately threatens a smothered mate. There is only one way to prevent that mate, covering the mating square with your Soaring Eagle.
There is an article on Tenjiku Shogi that describes how the pieces move. What would be the point of duplicating that information? Knowing how the pieces move might be a necessary condition, but it is not a sufficient one to become a good Tenjiku-Shogi player. If you don't know any opening theory, you will be slaughtered in a few moves by someone that does.