
Let's talk a bit about Yamato first:

Construction of Yamato began in 1937 and she was launched in August 1940. After trials, Yamato was commisioned December 16th 1941.
In February Yamato became the Flagship of the Combined Fleet in 1942, under command of Admiral Isoroku Yamamoto. Later on, the role of Flagship went to Yamato's sister ship Musashi.
Both Yamato and Musashi didn't see much action, firstly because they consumed lots of fuel, and also, the Japanese wanted to keep them for a final confrontation which never came. There was a third ship in the Yamato class, being Shinano, however, when the war started, it was clear that aircraft carriers would be the ships to go for. So Shinano was converted into an aircraft carrier.
All too often you read that Yamato never scored a hit in combat. However, lately it is believed that Yamato fired during the Battle of Samar at several US Navy ships. One of them being the escort carrier USS White Plains. On still from a US film reel near impact can be seen around USS White Plains. According to reseach by Robert Lundgren Yamato scored at least one hit on USS White plains incapacitating it untill the end of the war. More so, these salvos were fired from +/- 15 Miles/24 KM distance and so the impact would have been one of the longest range so far.
Yamato's armament configuration changed over time and I'll post her stats at the time of Operation Ichi Ten-Go:
Full displacement was 72.809 tons
Length: 263 metres
Propulsion: 12 Type-Ro Boilers and 4 steam turbines 150.000 HP
Max speed: 27 knots
Crew: 3.332
Armament:
triple 46cm (18 inch) caliber 45 gun turrets (largest naval guns ever used)
2 triple 15,5cm gun turrets
12 twin 12,7 cm guns
52 triple 25mm cannon mounts
6 single 25mm cannon mounts
2 twin 13mm machine gun mounts
A number of Yamato's AA mounts were enclosed. This was because ofenormous blasts from the main guns. These enclosed mounts were crew protection. Tests with animals on deck at the beginning of Yamato's lifespan revealed that many died from the blasts and others had severe injuries.
Here's a photo of Yamato's sistership Mushashi firing it's 46cm guns (all photos only for discussion purposes)

I'm interested in Yamato's last Operation being Ichi Ten Go.
Yamato and a battlegroup of 9 ships were to set sail towards Okinawa and help to defend the remaining Japanese troops there. Basically it was a suicide mission. There was just enough fuel to make it to Okinawa. The original plan was that these ships, once arrived at Okinawa would beach themselves and operate as fixed gun platforms. (In reality, most of the captains tried to muster as much fuel as they could hold of, as they didn't plan on beaching their ships, but in stead return after the battle)
Vice Admiral Ito was opposed to this berserk plan, but as an Officer in the end, he did his duty.
On April 6th 1945, Yamato, Cruiser Yahagi and 8 destroyers set sail for Okinawa. Vice-Admiral Ito was on board Yamato. Soon this battlegroup was discovered by US submarines, but these were too slow to keep up with the battlegroup.
The next day, Yamato was discovered again by spotting planes. Around 12.30 the first wave of enemy aircraft arrived. Although Yamato's 46cm main guns fired some of its 'bee hive' ammunition (Anti Air) it did do little harm to the incoming aircraft. Yamato was hit by several bombs and torpedos.
The Americans had learned from attacking and sinking Mushashi in 1944 and dropped most torpedoes just on one side. This way the crew of the ship had a much more difficult task of counterflooding to keep the ship level.


In the end 3 waves would pound Yamato, dealing massive damage to it's structure, AA crews and hull. 22 torpedo hits and many bombs later, Yamato was slowly moving in circles.

The list at that point was so severe that loose items started to move and drop off the ship.
At 2.23pm Yamato started to capsize to port. The ship rolled 120 degrees over. One of the weak points of the massive shells of Yamato is that they were very fragile. Went the ship capsized the 46 cm shells hit the sidewalls and detonated...with a huge explosion sinking Yamato. Some of the US planes closeby went down because of the explosion.

And that was the end of Yamato, taking 3.000 crewmembers down to the bottom of the Ocean. The largest battleship ever which was already obsolete when it was launched, in a world where airplanes would rule the seas in stead of battleships.
Cheers