Card-battling games have ruled the Japanese mobile charts for the past year or so, and now they're finding success in the west too.

And that's why Zynga is getting into the market, currently dominated by its Japanese social gaming competitors GREE and DeNA.

It's just announced the first two original mobile games from its Japanese development studio; monster-collector Montopia and spirits collector Ayakashi: Ghost Guild.

Both games have already been released in Japan, and will be available in the west for iPhone and Android, with Montopia out now and Ayakashi: Ghost Guild due later in the month.

Fight together

"This games are attuned to a certain type of player; they're for a niche audience that loves to go deep," explains Scott Koenigsberg, Zynga's general manager of games, on the decision to release the card-battlers.

"What's important is the value of the players' social connection - in terms of cooperative and PVP gameplay. This is something that underpins Zynga's business so it's a great combination."

The company's moved reinforces the importance of the card-battling genre, which although small in terms of absolute audience numbers, currently provides the most engaged and valuable players.

"PVP gameplay provides the longterm content for a lot of these players. That's why they come back to play every day," Koenigsberg adds.

Rage of Bahamut, the Cygames-developed and DeNA published card-battler has been a top grossing game in the US on iOS and Android, with DeNA also finding success with the release of Blood Brothers on its Mobage platform.

Similarly, another PVP-focused game - Supercell's Clash of Clans - is seeing success on the top grossing charts.