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SNKʼs popular game series Samurai Shodown converted to PC!

Samurai Shodown by SNK

SNK Corporation, headquartered in Suita City, Osaka, is a game manufacturer that owns the intellectual property (IP) rights of many popular game titles, including fighting games, which develops games for a variety of platforms and conducts their licensing business.

In June 2019, the latest series of Samurai Shodown, known in Japan as Samurai Spirits-one of SNKʼs most popular games-was released for both PS4 and Xbox One, and then for multiple platforms such as arcades, Google Stadia, and Nintendo Switch. In addition, SNK decided to convert the game to Windows so that more users can enjoy it, which was developed in a short period of only three months, leading to the start of sales at Epic Games Store in June 2020. Microsoft Azure PlayFab was used as a back-end platform for this PC version Samurai Shodown. The introduction of the PlayFab platform not only provided strong support for creating an entertaining environment for players, but it also greatly contributed to shortening development time.

Azure PlayFab: Introducing a leaderboard (score ranking) feature for PC

In converting Samurai Shodown for Windows PC, which has been released for PS4, Xbox One, and Nintendo Switch, SNK selected Microsoft Azure PlayFab-a back-end platform that can create an environment for multiplayer game play over a communication network. PlayFab supports multiple functions to solve issues of game developers, including establishing a multiplayer-game environment and analyzing game data, which can improve players' game experience.

Takeaki Yamamoto, a programmer at SNK, who was in charge of programming around the network for the consumer version of Samurai Shodown, and used PlayFab for the PC version, talks about the purpose and background of introducing PlayFab.

"While looking for a back-end platform with a leaderboard (score ranking) feature, we found that PlayFab, which had been verified in another project, was already ready in the stage where plug-ins can be used," explains Yamamoto. "[We] determined that it was well worth introducing PlayFab from the perspective of cost effectiveness."

SNKʼs development team members became interested in PlayFab when they participated in an Xbox event. "We asked Microsoftʼs product team a question on what we need to do to do cross-play on Xbox, and learned about a service called Azure PlayFab," says Hisaya Nakata, a programmer at SNK who was the main developer of the PC version of Samurai Shodown.

At the end of 2019, a variety of services, including PlayFab, were tested for confirming the availability of the cross-play feature. During the test process, the superiority of PlayFab was confirmed, which has a number of features and is compatible with different development tools. According to Kohtaro Morimoto, a programmer at SNK who was responsible for research, PlayFab is equipped with a wide variety of add-ons available to other game development tools and services, which led to being one of the many other reasons why they decided to utilize it for this project.

"For this project, PlayFab was selected because of its multiple add-ons available that will enable easy introduction of other services in the future," notes Morimoto.​

Lineup of key SNK programmers from the project. Takeaki Yamamoto, Kohtaro Morimoto, Hisaya Nakata, and Masanori Tsuji

Azure Blob Storage and PlayFab CloudScript: Enabling secure use of game data

The leaderboard feature of the PC version of Samurai Shodown was thus implemented using PlayFab functions while other functions supported by PlayFab were also used in this conversion. One of those functions is Microsoft Azure Blob Storage, a cloud-based object storage service used for linkage, as illustrated in the following figure.​

System overview diagram for leaderboard feature, Samurai Shodown

According to Yamamoto, "In Samurai Shodown, players can create their clone called "Ghost" with their win-loss record analyzed/learned, and can upload this ghost data to Blob Storage to share it with other players. Direct write to/read from the PC may allow data to be analyzed by users; therefore the PlayFab CloudScript function is used to write/read data on a server, but not on a PC."​

Uploading and download data from Azure Blob Storage diagram

Besides the above process, the win-loss record for online multiplayer matches is stored in PlayFab, not saved by users on their own. "Allowing users to have the win-loss record may lead to data rewriting," says Yamamoto. He also says that this data analysis/rewriting issue is specific to the PC version, which rarely occurs on console versions. With the use of PlayFab functions, these issues with conversion to the PC version were solved, leading to speedy development.

Masanori Tsuji, a lead programmer and R&D lead programmer at SNK, who was involved in this project for management, has now realized that introducing PlayFab played a major role in this conversion project. "Actually, there is almost no other back-end platform with as many excellent features as PlayFab, including those for the consumer version development," explains Tsuji.

Yamamoto also talks about the user-friendliness of PlayFab, saying, "I felt uneasy about web-based programming because of my [lack of] experience; after actually using it, however, a smooth operation was ensured." Some questions could be resolved by translating and checking the English version forum, which reveals that effective use has been made of PlayFab without relying on support.

Creating an environment for matches, regardless of platform, provides users with added value

The PC version of Samurai Shodown, which achieved short-term development by solving network match game-related issues by means of PlayFab, has continued to offer an amazing game experience to many players. According to Tsuji, PlayFab has been used more effectively even after the PC version was released.

"After the release in June 2020, we have received a wide variety of opinions including failure information," explains Tsuji. "We have continued to reflect them in the update and make improvements so that players can enjoy our game. In addition, PlayFab has various analysis functions that send us analysis data on a daily basis. Typically, we have to measure and confirm various necessary values on our own, but the functions do them to some extent on our behalf, which is extremely helpful."

Due to the success of this project, SNK feels confident about the introduction of PlayFab. According to Tsuji, the introduction of PlayFab will be studied for potential future projects in which PlayFab can be used effectively. In complying with the requirements of these projects, Tsuji will select the best tool and service for each project respectively.

In response to the question about "PlayFab functions that the development members want to use if the occasion arises," Nakata answers, "I have an interest in the "PlayFab Party" feature to provide voice chat and peer to peer (P2P) services," while Morimoto answers, "While in the verification process for cross-play, I wanted to create a game using the match-making feature."

Tsuji thinks that the team wants to provide a service with improved cross-play experiences in which anyone can freely participate in multiplayer games regardless of platform. "We could use only a small fraction of the PlayFab functions in this conversion project, and haven't been able to use all services yet. We want to take a little bit more time to verify the functions, and find future applications that can provide a higher value-added service to users and increase development efficiency," says Tsuji. He expects PlayFab to encourage successful development of a flexible environment for playing games.

Microsoft has provided enhanced support in Japan, including translating documents into Japanese, publishing case studies, and running a customer support blog and community support, which promotes the creation of an environment that ensures comfortable use of PlayFab.

The knowledge SNK has gained using PlayFab obtained in this project is proving to be valuable for Japanese game manufacturers, who look to SNKʼs future developments and application of Microsoft solutions, including PlayFab.​

SNK programmer team