Updated. Originally posted 18th June 2019
29SS: Japan's Future Submarine
Flag Japanese submarine builder Mitsubishi Heavy Industries showed off the 29SS next generation submarine design. The design is also shown in Japanese Ministry of Defense sources suggesting official endorsement by the Japanese Maritime Self-Defense Force (JMSDF). Research and Development phase is planned from 2025-28.

Japan's current generation Sōryū class are among the largest and most sophisticated conventional submarines in the world. The new design appears based on the Sōryū class with its distinctive bow form and hull outline, but differs significantly in the sail and hydroplane arrangement.
JMSDF Future submarine outlook - Covert Shores

The 29SS' sail is reduced in height and faired in to a greater extent than the current boats. It's streamlined form is reminiscent of the Russian ALFA and AKULA classes although in fairness it's not a copy and there are other examples of a similar sail form. If anything the Japanese design is even lower profile.

JMSDF Future submarine outlook - Covert Shores
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The sail is also positioned further aft than on existing classes with the now planes moved to the upper hull, well forward of the sail.

JMSDF Future submarine outlook - Covert Shores
A Japanese Ministry of Defense document ( shows the same ‘Future Submarine’, detailing enhancements to the construction of the core pressure hull. The schematic in the center is the current Sōryū class.

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Unusually for a conventional submarine the graphic appears to show a pump-jet. These are optimized for faster travel which may be a hint to a shift in propulsion performance for a conventional submarine.
JMSDF Future submarine outlook - Covert Shores
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The latest Japanese submarines are reported to have lithium-ion batteries in place of Air Independent Power (AIP). It seems likely that this design capitalizes on Japan's growing experience and lead in the submarine application of this technology.

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