minecraft-assets/assets/minecraft/advancements/nether/obtain_blaze_rod.json

{
    "display": {
        "icon": {
            "item": "minecraft:blaze_rod"
        },
        "title": "Into Fire",
        "description": "Relieve a Blaze of its rod"
    },
    "parent": "minecraft:nether/find_fortress",
    "criteria": {
        "blaze_rod": {
            "trigger": "minecraft:inventory_changed",
            "conditions": {
                "items": [
                    {
                        "item": "minecraft:blaze_rod"
                    }
                ]
            }
        }
    }
}