Daioh

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Daioh

Title screen

Developer:	Athena
Publisher:	Athena
Producer:	Sakae Nakamura Noriyuki Takasaki
Music:	Shoutaro Sasaki
Program:	Tsutomu Tabata
Art:	Hironobu Tamai Kata Chumuri Numa
Release date:	Arcade: July 1993 PlayStation 4: November 2, 2023

Daioh (JP: 大王, lit. "Great King") is a vertical scrolling shoot em' up released by Athena in 1993.

For several years Daioh was never rereleased, though pseudo-sequels existed in Athena's Dezaemon releases, such as Daioh Gale.

In November 2, 2023, the game was rereleased as part of HAMSTER Corporation's Arcade Archives series.

For replay videos, visit the Video Index.

Gameplay Overview

Daioh is a 2-buttons shooter. There are 7 stages with a second loop that is accessed right afterwards. It features a checkpoint system after the player loses a life, while instant respawns are used during boss fights, with the exception of the stage 7/14 boss.

Extends are granted at 500,000 points then every 1,000,000 points. They can also be found in the form of 1UP and 2UP items.

Controls

• A button (Press/Hold): Fires the player's main weapon.
• B button (Press): Activates the player's bomb.

Weapons

Daioh has 3 weapons the player can use by collecting their respective item, each of them has its own unique bomb. The weapon currently equipped is indicated by the color of the ship's cockpit.

All 3 weapons.

• Vulcan: Basic wide shot, it gets increasingly wider with each power-up collected. A set of two fireballs fired forward will appear at Level 7.
  • Bomb: Large fireballs travel in a circular motion. It deals low damage but has the longest duration out of the 3 bombs.
• Lightning Laser: Lightning shot with homing capabilities. Two lightning shots will be fired at Level 2, three at Level 4 and four at Level 7.
  • Bomb: 3 large lasers fired forward.
• Missile Shell: Missiles fired forward. Homing missiles will be added at Level 4.
  • Bomb: An AOE sphere that heavily damages enemies.

Note that none of the bombs grant invincibility frames to the player's ship itself.

Power-ups

There are four main power-up levels. Within a power-up level, there are smaller increments in which e.g. the Vulcan weapon gets slightly powered up but e.g. the Lightning Laser weapon stays unaffected. It takes 9 power-ups for the player to reach full power. Specific power-up levels have "spare" power-ups, represented by red P letters in the HUD below the lives count, if the player dies with these spare power-ups in stock they will respawn with their weapon at Level 2 instead of 1. The power-up levels where this happens are listed in the following table:

# of P items	Power-up level	Start with
1	Level 2	Level 1
2		Level 2
3	Level 3	Level 1
4		Level 2
5		Level 2
6	Level 4	Level 1
7		Level 2
8		Level 2
9		Level 2

Items

Icon	Description
	Power-up Powers up the player shot up to 9 times. 5,000 points when maxed out.
	Speed-up Increases the player's speed up to 3 times. 5,000 points when maxed out.
	Bomb Adds a bomb for a maximum of 20. 5,000 points when maxed out.
	Vulcan Changes to Vulcan. 5,000 points when already equipped.
	Lightning Laser Changes to Lighting. 5,000 points when already equipped.
	Missile Shell Changes to Missile. 5,000 points when already equipped.
	Shield Grants an extra hit and maxes out the player's weapon.
	1UP Grants an extra life. Found in stage 5/12 and dropped randomly.
	2UP Grants 2 extra lives. Dropped randomly.

Rank

Rank affects enemy bullet speed and the fire rate of certain enemies.

Daioh has a comparatively sophisticated rank system. Generally speaking, the rank counter starts at 0 (easiest) and maxes out at 320 (hardest). The rank counter can never go below 0.

Rank is initially affected by the difficulty setting:

Easy	+0
Normal	+32
Hard	+52
Super Hard	+82
Special	Fixed at 320

Adding to this, there are several actions during the game that affect rank:

• Power-up level: For every Power-up level, +8 is added to the rank counter. Therefore, the highest Power-up level 4 adds +32.
• Collecting 5,000 points items: Every surplus item pick up adds +4.
• Stage number: On every stage, a value is added to the rank counter based on stage number x 8. Therefore, +8 is added during stage 1, +16 during stage 2 and so on. The maximum is +56 on stage 7.

Curiously, player movement can affect rank as well. Three actions have an impact on rank:

• Movement pattern #1: When three or more enemy bullets are on screen, repeatedly moving in the same direction will add +1 per tap.
• Movement pattern #2: If a direction is held for 1 second then the opposite direction for 1 second while three or more enemy bullets are on screen, the rank is decreased by -1.
• Detection of repeated movement pattern #2: If movement pattern #2 is detected four times in a row, a +48 rank penalty will be applied; the penalty can be reset by tapping left/right three times, then up/down.

Lastly, stacking and using bombs has an affect on rank:

The rank increase resulting from stacking bombs is tied to a distinct bomb retention timer that ranges from 1-256 and slowly increases over time. If this timer hits 256, it resets to 1 and the rank counter is increased by +64.

Bomb retention timer
(# of bombs in stock + 3) / 4

The value resulting from this equation is added per second to the bomb retention timer. The values are rounded down and any resulting decimals are simply cut off. This means that with a bomb stock of 3, +1 is added every second to the bomb retention timer which leads to +64 on the rank counter after 256 seconds. The quickest increase happens with a full bomb stock of 20 which leads to +5 on the bomb retention timer every second: (20+3)/4 = 5.75 ≈ 5.

As a special rule, the bomb retention timer does not increase at all as long as the player holds only two or fewer bombs in stock.

• Bombing: Using a bomb decreases the rank counter and likewise the bomb retention counter by -32 each.

Gallery

Screenshots from HAMSTER Corporation's stream showcasing the rank system (Japanese):

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Scoring

End of Stage Bonus

The total bonus for finishing stages is based on two factors: Clear Bonus + Bomb Bonus.

Clear Bonus

With the exception of stages 7 (1-7) and 14 (2-7), each stage has a clear bonus.

Stage	Bonus
1 (1-1)	10,000 points
2 (1-2)	20,000 points
3 (1-3)	30,000 points
4 (1-4)	40,000 points
5 (1-5)	50,000 points
6 (1-6)	60,000 points
7 (1-7)	No bonus
8 (2-1)	80,000 points
9 (2-2)	90,000 points
10 (2-3)	100,000 points
11 (2-4)	110,000 points
12 (2-5)	120,000 points
13 (2-6)	130,000 points
14 (2-7)	No bonus

Furthermore, while stage 14 (2-7) doesn't have a clear bonus, each life in stock is worth 800,000 points. Seeing as the last life is still counted by the game and the final boss always grants an extend upon being defeated, this bonus is never lower than 1,600,000 points.

Bomb Bonus

Each bomb in stock is worth 5,000 points.

Tick Points

Due to its low damage and piercing properties, playing with the Lightning weapon earns more points than Vulcan and Missiles, even when it comes to zako enemies that are destroyed in a single hit. Therefore, using Lightning as often as possible will yield slightly higher results from enemy destruction.

Strategy

Item Drop Order

Items are dropped by power-up carriers and occasionally red-colored tanks. The items that appear are determined by the following cycle:

#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	#11	#12	#13	#14	#15	#16

After item #16 the pattern repeats. The item order resets once the player dies and starts over from a checkpoint, but it doesn't happen if the death was during a boss fight. The order isn't entirely static as the weapon drops always advance in a set order (Lightning->Missile->Vulcan), even after dying. For example, the player uncovers the first Lightning drop (Item #3) then dies, now the cycle looks like this:

#1	#2	#3	#4	#5	#6	#7	#8	#9	#10	#11	#12	#13	#14	#15	#16

Furthermore, when a shield or 1UP/2UP item appears it will take the spot of whatever item was meant to appear there. If a shield/1UP/2UP were to be the first item dropped, the Speed-up would become #2 in the item order, Power-up would be #3, weapon item would be #4 and so on.

There are a few item exceptions that don't affect the item order, such as the items spawned by the shield when picked up at full power (more information below) and the asteroids at the beginning of stage 6 that randomly drop bombs.

Auto-fire

While Daioh has built-in auto-fire it's possible to have a higher frequency than the default one (28,71 Hz being about the limit) by using an external auto-fire button. The damage done by the Lightning weapon goes unaffected, but Vulcan and Missiles will have a substantial difference when pointblanking with the higher auto-fire frequency.

Hidden Extend

Near the end of stage 5/11 a midboss appears. This is the only enemy in the game who always drops a 1UP when defeated. It is ideal to come into this encounter with the Lightning weapon, otherwise the midboss' arms will block the vast majority of the player's Vulcan/Missile shots and make it likely for the midboss to escape, missing the 1UP.

Shield Item

Picking up a shield item at full power.

This item will equip an armor that can withstand a single hit and max out the player's current weapon. If the player is already at max power then it'll act as a 5,000 bonus and release several other items floating across the screen. This is dangerous, since most of the items are power-ups and speed-ups that will be 5,000 bonus and are difficult to avoid it's easy to raise the rank by accident. On top of that, letting this item leave the screen will actually reduce the current rank by roughly half its current amount. As a result, this item is usually a bait and it's better to ignore it unless the player has no other choice.

Random appearance of 1UP

A 1UP appearing during the first boss.

Within the item sequence, there is a chance a 1UP/2UP item will appear. Normally their appearance is random. However, during a fresh boot (or after a hard-reset) by starting a credit at a specific point within the attract sequence it's possible to manipulate the game's RNG so that a 1UP can appear during the first boss fight. Furthermore, if the player's power-up and speed-up levels match it can be a 2UP instead, though the chances of this happening are lower.

Start a credit as soon as this demo begins.

This demo starts after the score ranking screen is first shown during the attract sequence.

Bugs and oversights

Boss 1 scoring bug

There is a major scoring bug present in the stage 1/8 boss. For some reason, using a Lightning bomb while being on the right side of the screen will decrease its HP by 16, the boss regains said HP afterwards once the bomb ends. The bug happens when the player uses a Lightning bomb while the boss' HP is 16 or lower, this will lead to the game thinking the boss has died and award the points for defeating it (20,000 points) multiple times while the bomb is going off. However, since the boss keeps regaining HP after each bomb the stage clear bonus and subsequent stage transition never actually happen. Because the points gained from this bug using the Lightning bomb go past the extend threshold the player can deliberately die once bombs have run out to continue this process until the boss escapes. A Lightning bomb can earn a maximum of 790,000 points, but because of very precise positioning required the player won't always get this exact number. Note that this bug needs to be performed while being far enough for the bomb to not make hit the head, if a laser makes direct contact with said weak spot the boss will die properly.

This bug is doable with the Vulcan and Missile bomb as well though not as effective. The Vulcan bomb doesn't earn that many points compared to the others and due to the fireballs spreading outwards they will inevitably kill the boss. On the other hand, the Missile bomb can earn more points than the Lightning bomb (roughly 1,3 millions) when the player is on the bottom right corner of the screen and the boss is at a high enough vertical position, otherwise it will die, because of this and the fact the boss periodically stops firing throughout the fight, the chances to suicide and regain bombs are more limited.

A demonstration of this bug can be seen in this video:

Infinite pattern

Like with a few other large enemies in Daioh, destroying the extend midboss in stage 5/12 fast enough will spawn a small swarm of zako enemies. Along with that this encounter happens to have its own checkpoint, meaning that if the player dies early enough they will respawn right before the midboss and have another chance to get the 1UP. The problem arises when the player destroys the midboss fast enough to trigger the zako waves and deliberately dies to them after collecting the 1UP, sending the player back to the midboss checkpoint. The easiest way to do this is by using Lightning bombs as they deal consistently high damage even from far away. 3 Lightning bombs can easily destroy the midboss (sometimes only 2 are needed depending on timing and positioning) making them perfect after the first suicide, while the other 2 types of bombs are inefficient due to either low damage (Vulcan bombs) or low range (Missile bombs).

It is important to note that, for some reason, the midboss doesn't take damage when it first appears and its HP only starts to decrease when it is about to shoot at the player, therefore it's better to wait for the ideal timing instead of using bombs from the get-go which could potentially ruin the whole setup. Furthermore, the suicide needs to be done at the top of the screen, if the player waits too long the stage will progress enough to make the game load the next checkpoint instead.

A demonstration of the infinite pattern can be seen in this video by Andrew98 (YouTube):

In March of 2013, Japanese scorekeeping authorities closed the scoreboard for Daioh due to the detection of an infinite pattern. The last top score submitted to the leaderboard is 99,999,999+α points by "兄弟制覇狙いの意外な結末...との仕様-T" in February of that same year. The last score submitted without the infinite pattern is 22,097,500 points by "超高速弾覇者わかさん". This rule has also carried over to JHA once Arcadia shut down. For more information visit the STG Hall of Records.

Version Differences

US region

Daioh has two Country settings that can be changed in the DIP switch menu: Japan and USA. The US version has every weapon and bomb available without the need to collect weapon items, making the game go from using 2 buttons to 6 buttons. Naturally, the US version is slightly easier to play than JP because of this. The player should be careful, however, as switching weapons at specific power-up levels too fast can cause a crash.

Controls

• A button (Press/Hold): Fires the Vulcan.
• B button (Press/Hold): Fires the Lightning Laser.
• C button (Press/Hold): Fires the Missile Shell.
• D button (Press): Activates the Vulcan's bomb.
• E button (Press): Activates the Lightning Laser's bomb.
• F button (Press): Activates the Missile Shell's bomb.

Weapon items

Weapon items are still present in the item order, however, since the player no longer needs to collect them to switch weapons, they are only found as Missile items and are always 5,000 points bonus regardless of the current weapon equipped.

1UP/2UP appearance

As described previously, the player can manipulate the game's RNG to cause a 1UP/2UP item to appear during the first boss by starting a credit at a specific point during the attract sequence, and just like the Japanese version, the game must be running in a fresh boot/after a hard-reset.

Wait for the score ranking screen after this demo.

The player has to start the credit after the animation in the score ranking finishes, once the letters stopped moving. However, the window that makes the 1UP appear is still rather small, waiting for a brief moment before starting can make the 1UP appear slightly earlier during the fight, but taking too long can exceed the time window and the 1UP won't be dropped.

Trivia

• The game would later recieve a remake known as Shienryu, which was released by Warashi in 1997. During that time, most former Athena employees worked there on Warashi.

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Gallery

See (Template Page)/Gallery for our collection of images and scans for the game.

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References & Contributors

• Page creation by Andrew98.