By Mike Bennighof, Ph.D.
For a generation, Japanese naval planners
intended to fight the U.S. Navy in a climactic
final battle in the Western Pacific Ocean.
They did manage to do so, though not with
the intended results, and not in the form
they had imagined.
To choose the proper time for a clash with the Americans,
the enemy fleet would have to be sighted long
before it reached its objectives. While the
value of aircraft for scouting purposes had
been recognized from the very earliest flights,
Japanese planners did not want to dedicate
carrier planes to the reconnaissance role.
Every spot on the flight deck would be dedicated
to strike aircraft. Instead, float planes
carried by cruisers would seek out the enemy.
Tone during Indian Ocean operations,
In 1934, the Imperial Navy laid down a pair
of cruisers with a design seemingly influenced
by then-current notions of hybrid cruiser-carriers.
But Tone and Chikuma were not
true hybrids. Originally designed as light
cruisers with 12 6.1-inch guns in four triple
turrets grouped forward, during construction
they were secretly altered to carry eight
8-inch guns in double turrets. Secondary weapons
numbered eight 5-inch dual-purpose guns, plus
a dozen 25mm anti-aircraft guns. They also
had a heavy torpedo armament, a dozen 24-inch
tubes mounted near the stern to protect the
bridge in case of a torpedo explosion.
Designed as modified Mogami-class
light cruisers, the planned 8,500-ton diplacement
rose to 11,215 on completion. Like other Japanese
cruisers, they had very light armor protection
but did feature many of the creature comforts
of the Mogami class: steel-tube bunks
instead of swining hammocks, cold-water drinking
fountains, air conditioning, and of course
several special compartments to store pickles.
While the odd gunnery arrangement kept the
entire after deck clear for aircraft handling,
this was only a side effect and not the designers’
primary intent. Japanese gunnery officers
had been unhappy with the performance
of their Type A (heavy) cruisers for some
time. “Treaty cruisers” of all
nations had been shaped by the 1922 Washington
agreement’s limits on tonnage and armament,
mixed with desires for high speed. The results
were lightly-armored ships, with great length
to generate high speed without excessively
Lightly-built, very long ships like the
Japanese heavy cruisers (note their non-existent
armor protection in Second
World War at Sea series games) twisted
and warped after pounding in heavy seas. Sometimes
this became excessive enough to damage their
structural integrity — Mogami for example had to be completely rebuilt after
her maiden voyage.
But even when the damage did not affect
the ship’s handling, it still could
degrade her long-range gunnery. A warp of
just a few inches in the gun mounts’
positions would throw off ranging, given the
large distance between the forward and aft
turrets on the 631-foot Nachi or Atago (almost
as long as a battleship). So for Tone and Chikuma, the design placed all
of the main turrets forward in a close group
to enhance accuracy.
The aircraft arrangements on the after deck
could handle eight seaplanes, but did not
include a hangar. Japanese designers considered
the speed gained in launching aircraft to
be worth the weather damage inevitable incurred
by the seaplanes. With the big guns placed
on the other end of the ship, the aircraft
would not be subject to blast damage and aircraft
could be launched during a gunnery action,
something not possible on a conventionally-designed
cruiser. The two cruisers rarely operated
their full complement, at times carrying a
few as one aircraft.
Chikuma prepares to fire a broadside,
Tone completed in November 1938 and Chikuma in May 1939. They operated
off southern China in their early years, and
then with the First Air Fleet in the early
stages of the Great Pacific War. A seaplane
from Chikuma scouted Pearl Harbor before
the Japanese attack, and both cruisers deployed
their seaplanes to scout for the carriers
during the operations in the East Indies and
Indian Ocean, at Coral Sea, and at Midway.
Neither cruiser suffered any damage until
the fighting for Guadalcanal. Again they accompanied
the carriers, and American planes damaged Chikuma at the Battle of Santa Cruz
in October 1942. But they remained with the
carriers and were not committed to the savage
surface actions off Guadalcanal, and then
spent most of 1943 in the central Pacific.
Both went for refits during the year, receving
an additional 57 25mm anti-aircraft guns,
most of them mounted on the broad aircraft
deck. That greatly reduced their seaplane-handling
capacity, but by this point, Japan lacked
planes and pilots to give them full complements
In March 1944 the two cruisers along with Aoba entered the Indian Ocean to attack Allied merchant
shipping, one of the very few uses of Japanese
surface ships in this role. On 9 March Tone sank the 7,840-ton British freighter Behar, crewed
mostly by Indian seamen. Before abandoning ship,
radio officer Henry Gordon Cumming sent off
a distress signal.
Chikuma under air attack at Rabaul,
Tone took 114 men aboard, and ten
days later, Capt. Haruo Mayuzumi ordered them
arrayed on the aircraft deck. Apparently randomly,
Mayuzumi selected either 65 or 69 of them
(witnesses could not agree after the war as
to how many died during the Tone’s shelling of their ship), who were shot
on the fantail when Mayuzumi refused them
the honor of death by sword and pitched into
the Indian Ocean. These included 10 of her
14 officers, and most of her Royal Navy gunnery
and sonar crews.
Mayuzumi did not survive the war, but his
superior, Vice Admiral Naomasa Sakonju, took
responsibility in his 1947 war crimes affadavit.
“In view of the fact that the Allies
are lately killing Japanese prisoners of war
at Guadalcanal by running tanks over them
and are often bombing and torpedoing Japanese
hospital ships, causing many casualties,”
the admiral wrote, “the H.Q. came to
a conclusion that the Allies are aiming at
the reduction of Japan's manpower, and H.Q.
decided to retaliate.”
Both cruisers accompanied the carriers at
the Battle of the Philippine Sea, but at Leyte
Gulf were part of the surface force that fought
the action off Samar. Chikuma was caught by American planes the next
day and destroyed; Tone survived the
battle but was sunk at her moorings in Kure
by American carrier planes in August 1945.
The two cruisers appear in several Second
World War at Sea series games, and presented
a difficult design decision: Should they receive
their full potential scouting capability,
or the same as other Japanese heavy cruisers?
Since the number of aircraft carried varied
from operation to operation (and sometimes
within a single operation) we gave them an
extra scout plane.
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Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and award-winning journalist, he has published over 100 books, games and articles on historical subjects.
He lives in Birmingham, Alabama with his wife, three children and his dog, Leopold.