The Black Tides of Heaven by JY Yang

The Black Tides of Heaven by JY Yang is the companion novella to The Red Threads of Fortune, with the two novellas having been released simultaneously. I happened to read The Red Threads of Fortune first, not for any particularly informed reason — I think I happened to have seen more marketing for that one when I made my preorder. This review will contain a lot of comparisons between the two novellas but I will try to avoid spoiling the other.

Mokoya and Akeha, the twin children of the Protector, were sold to the Grand Monastery as children. While Mokoya developed her strange prophetic gift, Akeha was always the one who could see the strings that moved adults to action. While his sister received visions of what would be, Akeha realized what could be. What's more, he saw the sickness at the heart of his mother's Protectorate.

A rebellion is growing. The Machinists discover new levers to move the world every day, while the Tensors fight to put them down and preserve the power of the state. Unwilling to continue to play a pawn in his mother's twisted schemes, Akeha leaves the Tensorate behind and falls in with the rebels. But every step Akeha takes towards the Machinists is a step away from his sister Mokoya. Can Akeha find peace without shattering the bond he shares with his twin sister?

Black Tides of Heaven follows Akeha, the twin of Mokoya, who was the protagonist in Red Threads of Heaven. As well as following the other twin, it is also set much earlier in time, following the twins (always from Akeha's point of view) from childhood until their thirties. While Red Threads had a lot of physical/geographical world building that drew me into the world and made me want to learn more, Black Tides had a lot more social world building. We got a more thorough explanation of the attitudes towards and treatment of gender, which was only hinted at and encountered obliquely in 

Red Threads.

The social treatment of gender was very interesting, actually. Children, when born, are treated gender neutrally until they choose their gender when they feel ready. At that point it is usual, but not compulsory, to visit doctors to have the chosen gender biologically assigned. My impression was that it was something like puberty being delayed until desired, but aspects of magic were involved.

The story itself was presented in widely spaced chunks of time, showing us significant events at different stages of Akeha's life. As the "spare" twin (next to his sister, the Prophet), he has a very different set of issues and worries in life. We also learn about some events that are important backstory in Red Threads but from Akeha's point of view. I'm a bit torn as to which is the "best" reading order for these two novellas. Black Tides is the stronger volume, in my opinion, and packs more of an emotional punch. Being set earlier in time, it's also a logical choice for reading first. However, I didn't feel that reading them in the reverse order ruined the story or anything like that. They work when read in either order.

I recommend The Black Tides of Heaven to anyone who enjoyed Red Threads of Fortune and to fans of fantasy more generally. Especially to anyone looking for fantasy books that explore gender in interesting ways. I gather that there will be another pair of novellas in this world coming out next year, and I am planning to pick those up when they do.

4.5 / 5 stars

First published: September 2017, Tor.com
Series: Tensorate, book 1 of two book ones
Format read: ePub eARC
Source: Publisher via NetGalley