Update: Kōhaku has launched on Kickstarter, and the campaign will run for 24 days. You may pledge for the basic version of the game with cardboard tiles, or go Deluxe, and get acrylic 3D-effect tiles and a neoprene mat.
In the solo mode, you are trying to outscore three koi pond constructors of scaling difficulty. The rules are available to download from the KS campaign page.
Our preview post below was published on October 17.
Kōhaku is a 1-4 player tile-laying game about populating a pond with koi fish and other animals. What makes it stand out from others of its ilk is that the tiles you'll be using have an acrylic overlay which gives them a 3D effect: fish at the bottom, insects flying over them.
In terms of gameplay, there is a grid of tiles in the middle, and each turn you'll be drafting two tiles to place on your tableau. You cannot put two fish side by side, and each of the other creatures and decorative elements scores according to what lies adjacent (e.g. frogs want dragonflies). The player with the most points at the end of the game is the winner. I assume that the solo mode is a beat-your-own score, but we will confirm it when the campaign launches on October 21.
(I assumed wrong: see update above).