I just split it so it's a new topic.
Yes, both "Horn of Heaven" and "Solemn Judgment" can negate the summon of "Jinzo" because he is not considered to be "on the field" during the activation of those trap cards. Since "Jinzo"'s effect does not activate until after he is successfully summoned to the field, there is no restriction to use either of these 2 trap cards to prevent him from hitting the field.
- A