Umineko - When They Cry (TV)

In ep 2 and ep 3, around 20:20 and 13:08 respectively, Maria is seen watching Higurashi no Naku Koro ni, sister work of 7th Expansion.

The witch Bernkastel looks exactly like an older version of Furude Rika, a character from the Higurashi no Naku Koro ni series, also by 07th Expansion. In addition to looking alike, the two characters also share the same voice actress.

The Beatrice art in the opening from episode 6 and on changed from her dress to a uniform.

After all the legal issues after Higurashi no naku koro ni - Kai, the authors decided to censor Uminkeo's murdering and corposes. You cannot see the most bloody and grotesque parts of the show until its disc sell.

The witch Lambdadelta looks like a younger version of Takano from the Higurashi no Naku Koro ni series, also by 07th Expansion. Also the voice actress for Takano when she was a child is the same voice actress for Lambdadelta.

Lambdadelta's name and appearance hint at her being connected to Miyo Takano from Higurashi. "Lambdadelta" (λδ) represents thirty-four when using Greek numerals and "Miyo" (三四?) can translated as "three, four" in Japanese.

The op for ep 12 and the rest of the story arc has been changed. The portrait in the beginning now shows Eva-Beatrice, along with Siesta 45/410, the seven stakes of purgatory, two witches Bernkastel and Lambdadelta, ex -Beatrice Virgilia, and Ushiromiya Ange.

The first part of the ending, the choir is singing/repeating "I surrender, I surrender, I love you" in Greek (Παραδώθηκα, παραδώθηκα, σ'αγαπώ)

Ep 19, the opening changes animation once again for the new story arc. The portrait at the beginning flashes through Eva-Beatrice, Beatrice in modern clothing, and Beatrice in her dress. A new furniture, Siesta 00, can between seen by 410 and 45. Maria is seen in her witches outfit and holding a staff.

In ep 21, around 18:00 the boat Ange is on is called Hanyuu-maru, named after Oyashirou-sama from Higurashi, Hanyuu.

The episode titles are all check moves

The Seven Stakes of Purgatory,also known as the Seven Sisters of Purgatory named after the corresponding demons of the seven deadly sins like Lucifer the sin of pride,Leviathan the sin of envy,Satan the sin of wrath,Belphegor the sin of sloth,Mammon the sin of greed,Beelzebub the sin of gluttony and Asmodeus as the sin of lust

In Dawn of the Golden Witch, it is revealed that the Siesta Sisters is a large force. Siesta 410 names two others, Siesta 127 and Siesta 20. Siesta 127 is said to be able to pulverize a human target at 2 kilometers, while Siesta 20 has a fire rate of 6000 rounds per minute. Since all the other Siesta sisters are named after weapons, Siesta 127 is most likely referring to the 5-inch deck gun which has a 127mm shell and a range well over 2km. Siesta 20 is likely referring to the M61 Vulcan Gatling Gun which fires a 20mm round and has a fire rate of 6,000 rounds per minute.

in episode 4, around 5:25, Kanon grabs a billhook with the same design as the one used by Rena in Higurashi

In episode 6 during the school festival, Jessica is cosplaying as Marisa from the famous Touhou doujin circle. You can also see Aya, Alice, Sakuya, and Reimu in the same band in order of appearance.

In episode 19, the stuffed animal Rosa gives to Maria, Sakutaro, looks very much like Kon in Bleach.

In episode 21 around 10.00, the policeman resembles Ooishi Kuraudo from the Higurashi series (both voiced by Chafurin).